Dude, you're losing it.

Look, I sympathize with people who say that a certain bike has been taking up the space in the rack or is just in the way in the yard etc. but the way to solve this shouldn't be to appropriate the bike. You notify the authority/owner of the place, and let them take care of it. What the police will do is, they'll take reasonable steps to try and contact the woner. In most cases this isn't possible, so the bicycle is auctioned off. That's what they do here in Finland, and I'm pretty sure a similar process exists in other places.