The campus police normally avoid causing problems for students, as long as they are not hurting anyone or being an obvious disturbance. However, anyone can look at the police reports each time the newspaper comes out and read a few sentences about a couple of students walking across campus with open containers of alcohol. A surprisingly high number of students somehow thinks that they can get away with this, and it remains a constant plague on the cops. As long as students are not brazenly breaking the law, they will not get a ticket, just a warning. The campus police are generally good-natured and understand that the trivial little problems students cause will not do any real damage to the campus or its residents.
The RAs tend to be a bigger source of write-ups than the police. While some of them will pretend not to hear the shouts of, "Pass me another beer!" emitting from your room, others are über suspicious. The best way to avoid a trip to the judicial boards is to keep the doors closed and stay relatively quiet while drinking. It is also good to keep in mind that RAs and residents are not allowed to party together, even off campus. Living in the dorms is definitely more restrictive than living off campus.