The only reason those thieves don't know they're there is because they aren't very knowledgable (if they weren't thieves I'd give them the benefit of the doubt, but you called it...)

Some might say that thieves should know what security systems may be there... I know if I was a thief I'd avoid stealing smart phones all together!

The best thieves already know what security systems are in place, the real battle is making sure they are actually secure.