Do you think some players are....?

Singled out by the refs and treated worse than others, and that sometimes the refs talk before the game and say "watch this guy, he's always off side" or "this guy is dirty, keep an eye on him and penalize if he does anything wrong" i really reckon they do, players like o'donnell, moi moi, gallen and watmough always getting penalized and seemed to be called out on every tackle for being offside, being told to get up more than others etc. anyway, do you think some players are treated unfairly and targeted by referees and if so, who?