Settle a stupid argument for me: forbidden vs strictly forbidden

[Peelee]

I mean laws like those in a penal code. But no, I've never seen anything like that, just the speed limit and, on occasion, signs that warn you that your speed does indeed get checked on that road.

Well sure, in penal codes it's useless, but that doesn't mean it's not used for legal purposes. In zones like that (IIRC drive into Virginia and you'll see a sign like that immediately), it's effectively saying "we have instructed our cops to not go easy on people" and letting the public know.