Pretty sure the cops can give any and everyone a canary for absolutely no reason, even a brand new car if they suspect something is up, or if they just have a grudge. The canary isn't saying 'you have something wrong', it says 'we suspect you have something wrong and we're gonna make u go over the pits just cos we can'. And most of the time yep, they'll find something. But even with an engineering certificate, they can slap u with one under the suspicion that you've made mods since... just to d1ck u around
Correct me if I'm wrong, but pretty sure I've read this in several other threads.