Smartphones at present are small surveillance devices vaguely dressed up as a tool. That medicine is far worse then the disease. I’m going to say at least a very plain description and open/closed signs need to be up.
Las Vegas wouldn’t be the same without all the lights. Where I live there’s a limit to one moderately-sized sandwich board, and I quite like it. Somewhere else they might want totally bare streets. All could be accommodated.
I did say “at present”.
You can install LineageOS (assuming you have a reflashable piece of hardware) and run it in airplane mode, it’s true, although that itself is slowly getting more difficult as everything gets app-ified. Just doing stuff the boomer way is easier in practice, in my experience - which, again, is at present.
If we’re allowed completely changing the way the telecom and tech sectors operate ahead of time, yeah, I guess we can get rid of physical signs and just look at the world through our phone screens. That’s obviously a taller order than adding a single regulation, though.