When you get into Barnard, one of the first things you will start to read are all the rules. You will probably worry that you might get in trouble at school for doing something, and your parents will be so pleased to see that the College takes such a strong disciplinary stance. However, the moment you step on campus, all of those rules will go out the window. In fact, the only rule that is enforced at all by the school is that you must show ID before entering a college residence, and even this is oftentimes bent. It's not because Barnard doesn't care about you, but because it has better things to worry about. Strangely, more rules are enforced by other students than by the College. If you smoke in residential buildings, for example, you can expect that someone will complain about the smell.
Kind of like how the security at Barnard is just there for looks, so are the rules they are supposed to enforce. There are also tons of things that you aren't supposed to bring into the dorms, such as alcohol and anything with an open flame, including candles, but don't expect the desk attendant to say anything to you about whatever you might bring to your room. The desk attendants are a little bit stricter in the freshman dorms, but even they aren't too concerned with what students do in their rooms just as long as it's not hurting or bothering anyone. Out of respect, students usually "hide" contraband, but there's not really any need to.