If Mayweather wanted a real fight, then he could have agreed to the proposal by Manny Pacquiao for a rematch. But he refused the proposal, and said that he is no longer interested in professional boxing. So for him, he is in this fight only for the money. I don't think that there is anything wrong here. He will get a few tens of millions of USD, for spending a few hours on the boxing ring. Not bad for a retired boxer who is almost 44 years old.
He will not do it, i don't remember any rematches that he agree to play with, and Mayweather will not let his guard down, he will not let other people win the game because they might do like what he did to them, if he will make a rematch with Manny expect that it will create a tons of money again, but the thing is he will not be the winner this time and I am sure of it, and if ever I will not bet in this game, I rather bet in not so well known boxer rather than a game with Floyd.