Originally Posted by
Kedosto
Put your lock on it and it immediately becomes yours again. At that point you’ll be in possession of a bike registered to you. Cutting off the other lock will be well within your rights, as the lock is on a bicycle that the other party cannot prove is owned. Simple.
-Kedosto
There is something to be said for this tactic.
If you know it's yours and are SURE it's not one that just looks like yours...
Take it back. The thief who stole it from you isn't going to call the cops on you.