I agree
Yes, it's what I've always stressed, it's one thing at home although they should still eat 'nicely', but when out they have to know what to do.
Plus with any job you never know if you'll be sent on a training course, or have to stay in a hotel, or go to a posh lunch do. It's the same principal with the food, if all they'll eat at home is chicken nuggets then they'll be embarrassed at a proper restaurant.