[footfootfoot]

I'm with the let it slide crowd, Don't think about evening-up the score. Don't forget either. I'd set my cam to motion detect until I got to know what to expect of this guy, unless there are specific rules forbidding it. I'm not sure what right to privacy you can expect from a room mate. You may also want to leave a papaer trail as in making a formal complaint with your RA just incase things get worse.
finally, I'd be up front with him as far as YOUR expectations of privacy are concerned and promise him you will report him (again) to the school.

people can suck but he may respond to your setting limits.