Is it ever appropriate to talk on your cell phone while eating in at a restaurant?

I was in a restaurant today, and not a cheapy one either ;), and a gentleman was very loudly talking on his cell phone. I suppose he was trying to be heard over the restaurant chatter. He made no move to get up and talk in a corner of the restaurant and the conversation was quite long. He did not even receive the call but made it himself and he was not dining alone. Apparently he wanted to give his dad updates on his drunk buddies and cage fighting. Now the couple did not look drunk or inappropriate at all so I have no reason to believe that they don’t know proper social etiquette.

Have you ever been in a similar situation? Did it annoy the heck out of you? But more importantly is it ever appropriate to take a phone call in this scenario (perhaps a brief call to check on the kids?)? And furthermore what makes people think that it is appropriate (even after receiving nasty looks from other patrons like myself)?

I know a couple people commented on this during this thread but it wasn’t many so I thought I’d ask anyway.