There's actually a few research papers (one of which is included below, if you've got a NEJM sub) out there on cheating in medical school (another form of dishonesty) being a major predictor (58% more likely) of disciplinary action by state medical boards:
Papadakis MA, Teherani A, Banach MA, et al. Disciplinary action by medical boards and prior behavior in medical school. N Engl J Med 2005;353:2673–2682
Basically, if you're willing to be dishonest when you view it as harmless and have very little incentive to be honest, you are way more likely to be dishonest when your *** is on the line. That's why adcoms take such behavior (fraudulent actions and cheating) so seriously, as they are a good predictor of whether one will cheat in medical school and carry that level of dishonesty into their future practice. The same kind of person that thinks an ID is just a needless barrier to their getting into a club or bar is the sort of person that will think certain pieces of paperwork aren't worth doing and use the copy forward function, never even reading the prior notes, for instance.
I do think that the drinking age should be 18, personally. But I also feel like anyone that is foolish enough to use a fake ID should be ready to face the consequences of that action, be they mild or not. There's plenty of ways to get drunk at that age that are far, far less risky. Getting a fake ID and using it in public to illegally purchase alcohol shows a level of prior planning, disregard for consequences, and disregard for the law that getting a bottle of wine or a six pack from some legal age person on campus.