That sounds like what my roommate did while I was living in my first...and only...dorm room! People are rude rude rude!!!!
I hated the university, and at the time I still didn't have my drivers license (though I'd had a car for the last two years...yes I know, loser me). My SO would come get me and take me out to dinner, shopping, and back to his house nearly every day after classes, to the point where I was primarily staying there (only sleeping in my dorm once or twice a week). I finally told her that I was moving out for good, essentially without anyones permission, taking my stuff back to my parents (who lived 45 minutes away, and fully understood my plight), and staying mostly at SO's house. I came back the day after saying this, and she had pushed all of my stuff into the corner, brought in giant real Christmas tree, fully decorated with lights and ornaments, and a FULL SIZE MASSAGE TABLE, on which she was massaging her half naked friend
She had even "reported me" to the school for moving off the premises without permission, without notifying anyone (I was a freshman, apparently there are rules about that kind of thing as a first year, but I didn't care, and neither did my parents). And people WONDER why my parents bought me a house to live in and I switched to a better school. This girl would sit on her bed at night while I'm trying to study, with a giant container of Edy's Brownie Ice cream, and yell full volume at the TV (yankees games)...with her "5 steps to being thin" note cards on the wall...yeah...really bad experience.