I graduated awhile ago, but frat houses didn't really have special privileges compared to the average dorm when I went there. "Squatting" in a frat house living area would have been roughly akin to "squatting" in a random dorm's common area - some random person on the street would get in a lot of trouble, but not necessarily a fellow student. Also campus public safety were pretty laissez faire compared to other places... we used to grab tables in the main admissions building after hours and play beer pong on them (mostly underage).