Not, strictly speaking, true.
Police have an unwritten rule.
It's called "The Rude Rule", they will pull you over if you do something rude. And after they've run your plate and the owner's record, try and figure out what law you were breaking when being rude...
Don't break the law* and always be polite, and you will very, very seldom get pulled over!
* Possible exception: Never delay traffic by strictly obeying the speed limit, go with the flow, there really is safety in numbers!
Ya think?