With the stolen bike, if the vanmoofs are stealthy enough to no get caught in the act, it might go pretty fine as I assume the thieves won't file police reports. Now if they already sold it, things might get hairy... in my place when your car gets stolen and you file a report you need to provide all kind of documents which a stolen bike owner won't possibly have. So I guess approaching the same way for theft of expensive gear (need to provide ownership proof) could curb it a little. And yes, I know also cars get stolen.
It is a little different but on one occasion, in France, some guy sold a computer online, sent it, and never got paid. Pissed off, he broke in the crook house and took back his computer (plus a few other things, not smart...), they both sued each other, the crook ended up in prison for 2 months, and the one who broke into his house had 4 months suspended sentence. But even if he just took back his computer, he would still be guilty, but the judge would most likely have handed out a lighter sentence.