College roommate advice!

scenario; private, liberal arts college in large city. 4 girls, with private bedrooms, 2 baths, common living room and kitchen area.
One girl caught by RA for having booze in the room. Penalty was no visitors in room for a week.
Same girl stashed alcohol bottless in common area in another girls ottoman, found by another roomie.
Girls had ‘talk’...rommie claimed would not happen again. Another roomie, while talking to “boozey roomie” saw more alcohol bottles in her room. Another ‘talk’. Girls feel one roomie, who is bothered by booze and doesn’t want to get in trouble because of ‘boozey’ is overracting. ‘Boozey’ claims she feels like roomie is her mother.
College has no tolerance policy. All girls are 18.

I’m the mom of the one they think is overracting. My first impulse is too bitch ‘boozey’ out and talk to her parents. Not saying that is the correct approach. What would you do? As a parent? As a college student?
If roomies are caught with alcohol in common area, all will be in trouble. Should the RA get involved?
Parent weekend is coming…my daughter doesn’t want to me to say anything, BUT I’M PISSED OFF!
This college is 29K per year…I know partying is part of the whole thing, but where is the line drawn? This ‘boozey’ roomie goes out and stays out all night and brags about getting into bars and getting sloppy drunk…grades are bad and family is well to do.
Anxious to hear opinions. I could care less what this girl does, but when it involves my kid, I get interested. But I don’t like snitches, either.