I think you're being a bit pedantic about it. It's hardly like it has blue and yellow chequered patterns down the side, or a blue light on top, or even "POLICE" written anywhere over it.
I've seen quite a few episodes with that van, and i'd not even noticed this "shield/badge" thing you refer to.
It's designed to make you think they are of some authority, especially to the folk who aren't clued up.
I've seen quite a few episodes with that van, and i'd not even noticed this "shield/badge" thing you refer to.
Then you haven't seen the same van then.