Maybe they should a "No Cellphone" area like the no-smoking... Or hell, just skip a dozen years, and billions of wasted tax dollars, and just move them outside with the smokers. But that would kind suck for me, I smoke... The paint could be amusing though, people fighting over window tables for better reception.
Something really needs to be done about excessive phone usage in public. I smoke, and know it bothers some people, so I don't just light up anytime any place I feel like it. It's not that tough to show a little respect for other people (not to mention it's the law now...). Too bad there isn't some device that would trick a cellphone into think it was getting a weak signal, so the offensive user would need to move a few to a better location, not quite an all out jammer, as that would be illegal, and also just the mention would bring the wrath of the forum...