Regarding the camera getting stolen off your car: It is possible someone could cut the wire and remove the camera, but it would be worthless to them as it would not include the power cord (which connects to one of your reversing lights) and the wireless transceiver (both of which are inside the trunk). Also, this camera has a special power cord for your GPS unit that has a little receiver inline with the cord--and the thief would not have that either.
As for maintenance: there is none. No batteries, nothing to clean.