That was their style of party and happened after the hell week ended.
I wanted to convey that professors can come if they are invited. But students won't because alcohol is prohibited in campus.
Let me put it this way:
Rusty is close to Cathy but he won't invite her to the parties because of alcohol and all competition they hold.
Bella would only come if Jill or MC invites
Hope that clears it and that's why professors won't be invited not because they don't want to come.
Did anyone realize, preps had tons of alcohol in open and Jade, Burke didn't have any issue with it