Former England defender Danny Mills has claimed that footballers will do all that they can to try and gain the upper hand on the pitch.
Chelsea's players were criticised for surrounding referee Bjorn Kuipers during their Champions League exit against Paris Saint-Germain on Wednesday.
Mills told BBC Sport: "Players will try to gain any sort of advantage they can, by exploiting all the grey areas.
"The reward is greater than the risk, and so long as that is the case, players will try to take advantage of that. You have to because the margins of error are so small.
"Alan Shearer was a magnificent footballer, but every time you touched him his knees collapsed and he went to ground."
PSG striker Zlatan Ibrahimovic described the Blues' players as "babies" following their reaction to the Swede's tackle on Oscar in the 2-2 draw at Stamford Bridge, for which he was sent off.
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