About ten years ago, when my wife and I had just met, we took an old ex British Army Land Rover across the Pyrenees from France to Spain, far off the beaten track.
We spent a couple of nights in an old mountain village on the French site, where we found a small restaurant where the daughter did the cooking and mom looked after the front of house and where we were being advanced from being perfect strangers to long lost members of the family within a day or two.
Every night, we observed a number of families eat there, with kids as young as three and under being expected to behave in a respectful fashion. There was no running around, no screaming, no fighting. It really impressed me, at the time.
Today, my own three year old knows what's expected from him when we go out to eat. It doesn't always work out, but like you, we always follow through, even it that means, rarely, that we have dinner packed up to take with us.