Your roommate does it. Your brother does it. It puts you at higher risk of sexual assault, greater risk of fatality in a car crash, and makes you more likely to get cancer. If you're under 21, you're out. If the fact that drinking massive quantities of alcohol can have some serious repercussions of its own isn't enough to dissuade you from tipping the bottle, consider the legal consequences.
College is a safe little cocoon.
A safe haven where nothing ever happens and nobody gets caught. Of course, if you're caught once, that's all it takes, and legislation is in Congress to make it a requirement for universities to contact the parents of students caught drinking underage. Realistically, the drinking age in the United States is perhaps a little obscene. A little revision might be necessary there. We have a drinking age for good reason.