that's tough. i've definitely taken unlocked bikes out of alleys before without a second thought, and been chastised on these boards for doing so. once the bikes were at the trash cans, so i knocked on the door to be sure they were fair game and got permission. another time it was a commercial area and cold and rainy.

locked bikes though, i don't know. i once left a bike locked up outside a co-op for two months while i went to el salvador. it was winter, too. i definitely understand the temptation, but there's always that chance.

and then when the bikes start losing parts, it's like, "oh, man, i need to get to it before the thieves do," but i always end up asking myself what the difference is (between me and the thieves) and leaving the bike alone.