were you studying security, or ethics?

seriously though, if you park near more desirable bikes with cheaper locks (or not properly locked, or not locked), you should be set. unless two guys put the rack into their van and drive off with all the bikes. it happens.

this is NYC, but if you know how to lock a bike in NYC you're set...
http://www.youtube.com/watch?v=aTA3JsZWiec
http://www.youtube.com/watch?v=_8UpUj_8tWI
http://www.youtube.com/watch?v=FCbU83_G6nA

and yeah, you'll see crazy-expensive bikes on most campuses. usually they're the ones that always look new because they're the least used. high-end road bikes with platform pedals, high-end mountain bikes with no mud, etc. these bikes usually have the crappiest locks and the most clueless locking methods. all of these factors paint larger targets on them. and when they do get stolen, they're usually not reported or replaced because the owners never really used or cared about them... just an expensive gift from mom and dad.

a bike that would cost you $250 to replace isn't worth $250 to a thief. as long as there are bikes around that cost 4x more than yours, and there should be plenty, you should be fine with DECENT locks used properly.