Arizona is both an at-will employment state and a right-to-work state. Employers can terminate your employment without notice. Here are reasons they might let you go.
It's ok to say the guy might have been starving and that's why he stole the tip jar but if you or your spouse lost the day's tips would you be saying that?
There are a few reasons why you're seeing a large increase. Knowing why might not make you feel better but at least you'll know why and what to do about it.