Not to derail the thread....
This has happened to me, twice, so far: being part of a blanket stop of all drivers to check for DL's (and the usual fishing expedition, too, of course). Being of a mind to consider this a "show me your papers" and not knowing of any legal requirement to respond to such a request when there is no traffic citation involved, I have initially refused. Then, after a little verbal interplay back and forth, I have complied, just to be on my way.
So: IS there a legal requirement to show the DL with no RAS or is this another thing that cops do, because they have always done it, and because they can, and because, as I did, most people just want to be on their way, and, as you say, there is nothing to stop them?
If there is no such requirement, my response will be different, the next time.
Just to clairify... were you stopped, as in 'pulled over' by a police car with lights flashing, etc.... or did you pass through a 'Checkpoint' and they asked for ID there? I think police at 'checkpoints' have more leeway in demanding 'papers pleeze'....