I'd never have thought about it before, but I can understand the restaurants concerns.

I did take a photo of my tapas in Spain last week!!

Very interesting but not surprising when you see the results and the way people worship there phones

I don't think it would be so much of taking photos of the food. Its sitting down and just taking out phones right away instead of looking at the menus.
I can remember once taking a photo of what I was eating. It was in Madrid and the dish had flowers in it( edible ones) Beautiful. Usually the photos I have are at a bar with a cocktail in my hand!!
I actually make a point of turning the sound off on my phone when we sit down to eat.