You can read what Whites head coach Marcelo Bielsa and Derby County boss Frank Lampard had to say here on the matter. And read below the verdicts from opposition managers...
Is there anything wrong with spying on the opposition? Let us know your thoughts in the comments section below.
Chris Wilder - Sheffield United
"It’s been over exaggerated," said Wilder.
"It’s not something that we would do but I think the manager has been clever because the chant about Leeds United ('We all hate Leeds') will get a little bit louder now and they will love that siege mentality.
"You saw in their performance (against Derby), that it was them against the world, and I thought they were outstanding with it."
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.”