Yes I know this is just a movie (one I have enjoyed extensively), but just humor me.
They could have gotten rid of Payne easily if they had just told the principle about the fact payne had used a fricken hand grenade on school grounds.
They could have gotten rid of him for that and a lot of other things. But, there'd be no movie! To be fair to the writers, they did at least TRY to cover that by having Phillips tell Payne when he meets him "I don't care WHAT you do with those boys, as long as you keep them out of my hair". So it's implied that Payne could pretty much do as he pleased.
Whores will have their trinkets.