Found this on the indispensable BSNYC
also register your bike with the Chicago Police and get a sticker for your bike
awesome, thanks for posting!
...But what about those why registered their bikes long time ago?
Glad to see this, thanks for posting.
The goal of the sticker is to discourage bicycle thieves, as a pawn shop could easily identify the bike as stolen when checking the police data of "hot" or stolen bikes, community policing Sgt. Jason Clark said.
Would be interested to know how a shop would check this.