[jboot]

The problem with the "sit with you back to the wall" advice is that everyone at the table can't do it. I once had an acquaintance who made a terrible scene when he couldn't sit with his back to the wall at a restaurant (he came late and others were already seated).

I always identify the exits and make a note of potential cover. Many restaurants have large mirrors that can allow you to monitor spaces behind you. It is possible to do all this and not be a boor. ;-)

[livius]

LOL! I know, you really can’t have everybody lined up in the restaurant with their backs to the wall; there’s only so much wall space.

As you suggest, a mirror is a good solution. But of course, most people don’t notice what’s going on around them anyway, so maybe the very first thing they need to learn is vigilance.