I have heard this story many times. The police don't give a hoot about your app that says someone stole your bike. So as you said, the GPS is of questionable value in itself.

In the cases I know of, people had to go vigilante and go out themselves with a bolt cutter. One of them even saw his bike listed for sale a few hours after it was stolen, and went out and stole it back. Of course not everyone has the constitution or inclination to go crime fighting.