I know this is not a very helpful w.r.t. protection, however there is https://bikeindex.org/ https://bikeindex.org/ - recently I was listening to a Darknet diar

I know this is not a very helpful w.r.t. protection, however there is https://bikeindex.org/ https://bikeindex.org/ - recently I was listening to a Darknet diaries podcast https://darknetdiaries.com/episode/153/ https://darknetdiaries.com/episode/153/ which has a nice story about stolen bikes and what to do about it.