I don't think it's a d1ck move, even if you don't ask. It's a bike rack, it's meant for bikes, it's not being used for bikes, which means whoever paid to install it isn't getting their money's worth.

However, given that yours is the first case I've heard of a commuter being repeatedly targeted for obnoxious deflation, it's not a common thing. So if review of the tapes can identify the culprit and he can be dealt with, I bet you won't have to worry any more.

You could also look around in the back, even if there isn't an actual bike rack, there might be a pipe or some other secure feature that you could lock up to while keeping your bike out of everyone's way. That might be preferable to a rack out front in general.