Leeds United's 'spygate' saga has caused a lot of discussion over the last few days - here's a look at what other managers within the game have said about the incident.
Steven Gerrard - Rangers
"It's been a surprise.
"We have to protect the integrity of the game. I'm certainly someone who believes in fair play and respect.
"I think Leeds have overstepped the mark in this case. But it's not of my business thankfully and it doesn't involve my team.
"I felt for Frank of course but it is what it is.
"It's not something I have experienced personally but I think you've always got to be on your guard.
"In football it is natural that you'll always try and get any advantaged you can. You always take things into consideration to try and protect your team, tactics and game plan.
"It's not way to send some other people to training grounds. There's not a law in place and until there is a law in place it could happen again. I think the people that be need to adapt the rules."
Frank Lampard - Derby County
"Ready for my presentation - we do analysis too by the way!"
“I haven’t seen it, I’ve heard about it, obviously.
"It’s a funny one for me because I don’t really want to speak too much. I spoke a lot at the weekend.
“He gave an impression of himself. I haven’t seen Pep Guardiola give that, I haven’t seen Jurgen Klopp give that, (Mauricio) Pochettino give that.
"They do it behind closed doors, definitely, but they don’t do it to the public.
“It’s probably a nice eye-opener for the fan to see it, because most of these things are done behind closed doors.
"They’re done everywhere. There’s no amazement from anyone who works in football, they won’t be amazed in the slightest. It’s par for the course.
"It is what it is now. We all know what’s been happening across the board.
“It’s certainly a League issue now. It’s our League, it’s every team, so it’s up to them to decide what goes from now."
Unai Emery - Arsenal
“There are two things. One, is it legal or illegal? Two is fair play.
“I know him. In his career, above all in Spain, I know he is obsessive but a very big professional doing his work.
“For me, I respect him a lot. He’s one of the best coaches in the world.
“Everyone can have his opinion. Mine is only mine for my inside.
“I respect him a lot and his career… Everyone can have an opinion on if it’s legal or not. Mine is only mine.
“You can ask me. Did you do sometimes that? No.”
Chris Wilder - Sheffield United
"He (Bielsa) comes a different culture and we've encouraged the introduction of foreign coaches and managers. He's from somewhere with different rules.
"Is it ethical? Possibly not. Is it something we would do? No. But there are other parts of the game that upset me more, parts that aren't being addressed.
"He's done it, he's a maverick and it's part of this weird and wonderful world we call football. Diving about, going down, rolling about and then getting straight back up again when you've got someone booked or everyone dashing around a ref; those things really do my coconut in."
"He must have a crystal ball to know that Dean Henderson is going to try and dribble it out and then fall over," Wilder said on Leeds Uniteed's victory at Bramall Lane last month.
"If he knew we were going to miss chances, first-half, he must be a better manager than me. It's been blown up. It's like, maybe, going to a film star's house. You're allowed to walk around it but not in it. Perhaps that's a silly example but you know what I mean."
"Players diving about and getting people booked, rolling about and getting booked, maybe that needs sorting out first. If somebody rang me up this morning and said 'this is Swansea's team' then I'm not going to say 'no'. But it's the act of doing it."
"He has stoked the fire and created a lot of debate on this. It’s something that I wouldn’t do, and possibly the majority of English managers wouldn’t, but he has done it.
"I think it’s been over exaggerated. I think everyone is trying to find that edge, and sometimes they do it in a way that doesn’t really sit right with players, managers and supporters. But they are prepared to do it.
"Maybe there might be a change in the law. For me it needs a word, or warning, with the manager about future behaviour.
"People are saying 10-point deduction or a big fine. No, he’s just trying to get an edge, an advantage on a team. If the FA change the law, I would image it won’t happen again from Leeds United’s point of view."
Alex Neil - Preston North End
“What I do think is that where you can get a leg up and an advantage is hoping to deploy tactics that the opposition maybe won't be aware of
“That's been breached which I don't think should be the case. “I don't think it's normal practice in this country and I don't think it's sportsmanlike behaviour.
“What amazes me is that he's just come out and said he's done it, said he's been doing for a while and doesn't make any apologies as if he's not going to continue doing it.
“It's bizarre and if you ask any manager in this league or any other league 'would you mind that the opposition manager is going to come and watch your training session before the game starts', the answer would be yes.
“I think it's a little bit underhand.
“People will say it's using initiative to get an advantage but I wouldn't say it's in the best will of the game.”
“They've chose to do what they've chosen to do and I don't know how you govern that because every training ground is different.
“As you're fully aware we've got a path at the side of ours so he doesn't need to hide in the bushes he can just stand at the side.
“How do you stop someone walking down the side of the pitch?
“I think a lot's been made of nothing. I should be a wee wrap on the knuckles and a 'listen, don't do that again'.”
Neil Warnock - Cardiff City
"I was asked this week 'what would you do if someone came to watch us' - and I'd just encourage them because it'd confuse them!
"It's one of those things.
"Everybody gets accused at some stage of doing something, it happens.
"I don't think it actually affects the result of the game, just an eye-opener really on what you can do."
Claude Puel - Leicester City
“It’s different in England than in France.
“We have in England, all training grounds without fans. All the teams can work with a lot of quiet, calm around them.
“In France, it’s difficult to work (like this) all the time, some people try to look what the opponent can do. It’s a different thing.
“In England, it’s special because normally we have, all the time, calm around the players, around the staff, to prepare the next game.
“But of course this situation (with Leeds and Derby) can give another feeling.”
Nigel Adkins - Hull City
“We scout every team as well but when you say about sending someone to the training ground, it obviously didn’t work when we played them,” Adkins said.
“We weren’t in Christmas Day and I’m pretty sure he wouldn’t have realised Will Keane was going to play and obviously we won the game.”
“We have a real good analysis department here and we always watch the games so that gives you a good idea. We watch opposition’s press conferences to see if the manager turns around and says this player isn’t fit or has an injury.
“We have scouts going to games and again you are visually looking to see if somebody is struggling with something. Players all talk as well.
“I haven’t done it. I haven’t been down to watch opposition and I’ve not sent anyone to watch the opposition training. We go watch them play.
“There’s a lot of video footage available now, for example our own departments but video footage out of training sessions.
“If that’s his preference that’s his preference. I don’t think there’s a need to go and do it because I think there’s enough stuff out there anyway.”
From the weekend...
Mauricio Pochettino - Tottenham Hotspur
“There is nothing wrong with finding information about what the opponent is doing," said Pochettino.
“Thirty years ago it happened in Argentina. Not only Marcelo, all the managers. When I was 17, 18, 19-year-old all the managers like (Carlos) Bilardo or many, many others used to send people to watch training sessions.
"Here it's a bit weird, but it happened in Argentina.
“I remember in 1966 World Cup, how did the Argentina team behave? Remember, we always wanted to be more smart than the opponents. It's not a big deal what happened.”
Neil Harris - Millwall
“In all my years in football I have never seen anything like it," said Harris.
"I think it is completely disrespectful to other teams and the spirit of the game in this country.
“The fact he doesn’t think he has done anything wrong is disappointing.”
Nathan Jones - Stoke City
"When I was at Yeovil, for example, we didn’t have electric gates and so we always kept an eye on people walking their dogs!", Jones said.
"But no you don’t expect what we’ve read.
"We’ve got a very secure training ground and it would take somebody up to real no good to get involved."
Garry Monk - Birmingham City
“First of all, the normal reaction is the comical side of it, someone rustling around in the bushes and trying to spy," said Monk.
"I don’t really see the benefit of that.
“There’s the other side, the ethical side and what we do over here. We like to think it’s fair sportsmanship in this country and we don’t like to see any of that.
“It’s not the right thing to do, it’s not ethical.
“I suppose it’s more disappointing to hear something like that from such an experienced manager and such a world-class manager as he is.
“Once the comical value wears off, in this country we don’t see those things as the right things to do.”
Lee Bowyer - Charlton Athletic
“I think it has happened to us,” Bowyer said. “I think it has happened a lot of times.
“At our training ground you have got bushes and you get people walking down all the time who stop, watch and write stuff down.
“There have been a number of times I’ve seen people out there. Can you stop it? Maybe at some clubs. We certainly couldn’t because of where our training ground is.
“Alright, you might get a heads up on who is playing – but other than that I don’t know [how much it matters]. It is what players do on the pitch out there.
“You could have all the information but six of your boys might have an off day.
“Yeah, it’s an advantage because you get to know shape. We just try to do it by watching the games previously, so you have got half an idea how they are going to play.
“With Accrington on Saturday I will watch when we played them away and then their more recent games. I’ll make sure it is a mix of home and away, just to cover all areas.”