Compliance Plates

This is probably really obvious but i was just wondering
when someone steals a bike or a car why do they sometimes remove the compliance plate?
if they used it on another vehicle and they get even a half arsed rego inspection or blue slip inspection done
then it will show up as stolen. wouldnt it be useless once its removed?

I dunno why thieving scumbags remove them .... but then again I don't know much about thieving scumbags at all, but I've got a couple in my draw that I removed from track bikes that are still quite usable.