You have no proof that the last renter actually left the bicycle exactly like that (they may have left it neatly parked just a few metres away and someone purposely moved it)
How so? Gobee can just check where it was the moment the renter locked it.
the renter is quite likely to be a foreign tourist (fining them is near impossible without the benefit of a license plate like you have with a car).
Gobee uses digital payment systems, which are not anonymous.