Students may break the rules, but they do not get caught often unless its their freshman year and they live in a dorm. In that case, if the RA is at all savvy, they may write up the student(s). If this happens, the student(s) must appear in front of the Honor Court, which is made up of students from ASUPS (student government) who colloborate to figure out a solution to the particular situation. This may be changing dorms, writing an apology letter, expulsion (depending on the severity), or a number of other consequences. After freshman year, students can get away with pretty much anything as long as it doesn't directly affect the school.
If you live far enough away, security won't bother you, but then you have the police to deal with in regard to noise complaints. Depending on the neighbors, it's relatively easy to have people over, as most houses close to campus are rented by students. University of Puget Sound is not lenient, however, on plagiarism and will suspend or expell students depending on the situation. All of the school policies are contained in a book called The Logger, which is distributed to students every year. The University has an extensive Integrity Code outlining all of its expectations of students and describes sanctions like probation, eviction, and expulsion for code violations.