If this true, I wonder if all those that stole the bait car would get off if the Police are using 6 meters illegally. The lawyers would have a field day (no pun intended) with this.
I remember reading many years ago (I'm pretty sure it was in Popular Electronics, if that gives you an idea of just how long) about a guy who got caught in a speed trap in some small town. He did a little digging and found out that the town's license to use its radar guns had expired several months earlier. He contested the ticket, told the judge what he had found and the judge dismissed the ticket on the basis that the cop had used his equipment illegally.
So the answer to your question is probably "yes." But I hope the car thieves are too stupid to figure this out, if indeed it is the case.