I have reported crimes in the past, car that had been stolen, and a shop that had been broken into etc. I had the Police come to my house, search my house and search me and ask me questions. The Police even asked my neighbours about me. I was told, it is something to do with some people who did actually commit the crime, go and report an offence. Probably to cover themselves, should they have been spotted in the first place.Or any responsible person who knows the bike's location...
Don't know if it is possible, everything is traceable nowadays.Always possible to report it anonymously.
Given me another idea of something to photograph, the classic red phone boxPhone boxes still exist - IF you can find one!