Mental Note, don't let daughter go to Grad Bash, Check
On a more serious note I imagine it is similar to proms and after proms where certain kids get rowdy and do things prior to going and other kids just go to have fun with their friends and are not rowdy or do things beforehand. I imagine if you hang out with your friends on a normal basis and do drugs and alcohol that you would do it here also. If you don't, you wouldn't.