Well on a personal level I like the idea of embarrassing people into turning off their cell phones - but there's a good chance that the customer who's been embarrased, whatever the reason and whether they were in the wrong or not, is less likely to return. Not to mention that some diners have children in the care of sitters and cell phone contact is essential. And some idiot customers are just as likely to make their cell phones ring just to see if they can get a similar reaction.

The best solution I have seen yet is a large sign at the front door of my local jazz club that states very clearly "please turn off your cell phone before entering".