You guys are naive

Mayweather will be bored as hell, but ultimately safe. He's not going to pre-trial with murderes and rapists, he is already sentenced. Once the ridiculously long booking process runs its course he will be put in a cell most likely by himself, possibly with a non-violent high profile inmare.

In a way his time will probably be harder because he won't often have people around to help him pass the time. A game of cards or dominoes can be a mental life saver in jail.