As much as both my husband and I enjoy cooking meals at home, we also tend to wind up going out to eat at least once or twice a week, if not even more often than that. We both have very busy schedules and he works long hours, so sometimes it just makes more sense for my son and me to meet him out somewhere for dinner rather than to wait for him to make the 45-minute commute home.
And since we go out to eat all the time, our son is no stranger to restaurants, and he knows how to behave when dining with us. But that doesn't mean we expect him to sit there with no source of entertainment other than his charming parents for the entire meal. And that's why we always let him play with one of our iPhones or his Nintendo DS (while wearing headphones, of course) for part of the dinner.
Up until today, I never considered letting him have a little tech time as any sort of a problem.