The campus rules may seem strict, but there are always ways around them. The main concern is that you stay safe. If you do that, you shouldn’t run into any trouble with campus security or the CAs (community assistants—Northwestern’s version of RAs). Northwestern is very good about laying out the rules for freshmen right off the bat, so there are no arguments when it comes to your knowledge of what is allowed. Rules like those prohibiting coffee pots, lights in the dorm rooms, and overnight guests are easy to get around. The CAs can be very lenient with these issues; usually, if you keep quiet, they will, too. Policies about underage drinking are definitely the strictest, but again, be safe and campus authorities will not get involved. But if you wake up in the hospital, you may have a run-in with the administration. Overall, the CSOs (community service officers) and campus police do make their presence known, but if you don't give them a reason to bother you, they won’t. The CSOs are very nice, and they will wave and have a nice conversation with you, whether you are leaving the dorm in a skimpy skirt and tank top to go "party" or in your sweats to go study.
One policy that Northwestern is very strict with is plagiarism. Professors will always make sure that students are aware of the rules and consequences for such action. But let's face it: You’re at Northwestern. You are smart enough and fully capable to do your own work. Ultimately, University officials are there to keep you safe, and if you don’t create reasons to get yourself in trouble, they will mostly stay out of the way.