Manchester United manager Sir Alex Ferguson has stressed the need for privacy from the media when teams are training.
On Thursday, photographs emerged of what appeared to be a bust-up between Manchester City's Roberto Mancini and Mario Balotelli.
Mancini has since played down the altercation, although the incident has ignited debate over whether cameramen should have access to clubs' training grounds.
"You are protecting the possibility of success," Ferguson said. "Do ICI send an email to another bio chemicals company telling them their new discoveries in drugs? Does any major company tell its opponents what they are doing? I am sure they don't.
"Unfortunately football has a media profile which means cameramen want to be at training sessions. I think that is ridiculous but it makes it very difficult for a coach to do their work because you don't know where the information can go.
"I think it stopped at Real Madrid under Jose Mourinho, but there are some places where the press are in every day. This is what they expect.
"I know it happens in Italy. I don't know how you can do your tactical work.
"Fortunately, at our place, we can guard against it to a decent degree," Ferguson added, before joking: "Sometimes we get a photographer wandering over in the woods - but we can put wolves in there!"