If there is no reason to, the University Police will basically stay away. Don't antagonize or test the police, because the penalties just aren't worth it. Students at SBU are trusted by the police not to get out of hand, and in this way, almost anything goes. Keeping the dorm room door closed is always a good idea, especially when partaking of alcohol and any other substances. Keeping the noise down is also important. If noise levels get so disruptive that other students complain, trouble may soon be on its way. Stay good friends with your RA, having them on your side is always good. Most RAs don't really care what goes on as far as intoxication is concerned, but there are some who won't stand for it.
On the other hand, the University Police are very stringent about parking. Parking tickets seem to be the livelihood of Stony Brook Parking Services. They add up after a while, and they are quite annoying. Beware if you are handicapped: the police do a horrific job of enforcing handicapped parking at night, and so all the disabled parking spots are usually taken by the lazy population of Stony Brook students.