For two successive weekends, the England winger has been at the centre of a controversial penalty decision. Both against QPR and Aston Villa, Young was accused of going to ground far too easily in order to gain spot-kicks for his team.
And, ahead of the Sunday lunchtime encounter with Everton, Robson has issued his own words of warning. "I thought the one against QPR was a little bit harsh on them and it probably was a dive," he told BBC Radio Manchester.
Robson added: "But I have looked at replays of the weekend one and the defender did catch Ashley on the foot.
"Yes, he did make it a bit dramatic. If he had just gone down because of the connection on his foot, I don't think too much would have been made of it.
"But he is going to have to be careful because people are scrutinising him now. The thing is, in a really important game towards the end of the season there might be a blatant penalty and he won't get it because he has a reputation for diving."
Even Sir Alex Ferguson has admitted the ?18million former Aston Villa man has gone down theatrically, whilst also claiming both penalties were valid.
However, Robson feels it is wrong to single out one player for special attention when the problem is far more widespread across the Premier League, with the myth of it being a problem purely with continental players now exposed.
"Loads of players do go down very easily and do take a dive," he said. "It is not just within Manchester United. At most clubs a player will try to get a penalty if he thinks he can get away with it.
"If you get fouled in the box, go down but it has to be something that knocks you off balance."