Going back to the first 'penalty' (I didn't think it was). Barnes played the ball away from McCarthy, who was diving at it, then ran across him leaving his foot there, and was bought down. Two things the ref will take into account, first, was the ball under control, imo, no. Second, could Barnes have avoided McCarthy, imo, yes, he could of jumped over him. So my conclusion, is that Barnes went down on purpose, looking for a penalty.
All these highly paid young men are cheats, they all do it. Shaking hands before hand (fairplay) is a joke.