Many colleges have a problem with abandoned bikes. Students graduate, transfer, leave, and their bike is still locked to a rack. Over the years, the racks could become totally filled with abandoned bikes if the problems was ignored. So, many colleges post a notice of a week when few or no students will be on campus that any bike left on the rack will be put into storage by the campus police. If it is not claimed within a reasonable time (say, 90 days), it is then auctioned off.

However, letting each person decide for himself when a bike has been abandoned could lead to silliness. You stop for coffee every single day at 7 a.m. and lock your bike to the same post for thirty minutes. You come out one day, someone is cutting away on your lock. When the police show up, he says "Oh, I have seen this bike here every single day for six months...I thought it was abandoned".

Better that the police have a program where they "tag" a bike abandoned in a public area, and the tag states the bike will go to police storage unless moved with ten days. Then give the owner ninety days to reclaim the bike before the police auction.