Devil's Advocate points out (through some book on urban cycling that I was perusing at Barnes & Noble the other day) that when you lock up your bike with a bunch of other bikes, you make it easy for a thief to disguise his/her actions. This bike actually suggested locking your bike slightly removed from large racks filled with bikes. Of course, when you're talking bike shows, then you're talking a huge convention center or something full of rabid, theft-paranoid bicyclists.

I visited my Mom a few months ago in SF. Coming from New York, I was flabbergasted at how blithely people there lock up their bikes on the streets. Transplant some crackhead from here, and they'd have field day!