We see it all the time. We are out to dinner and it is late. (At least past my usual bedtime). And a family comes in with sleeping children in tow (or on their parents shoulder).
Can someone please explain to me the need to bring a child already asleep (or 99% of the way there) to a restaurant? Save for the occasional emergency situation, a child's sleep should be high on the priority list. There will be plenty of time for dinners when they are older. If it is necessary to get together with that group that day, have a lunch. Or an early dinner. Or get a babysitter! There are plenty of options that do not require a parent to be selfish and disregard the needs of their children.
If the child is that tired, they are not going to enjoy themselves. And more likely they will be cranky or grouchy if they are woken up. And forget about the next day. Any parent who is familiar with a child who does not sleep enough knows what I mean. I have posted about this before (check out the Archives for "Wake Up Happy" and other similar posts) and believe this is common sense. Except that I have learned that common sense is not so common.
We take our son's sleep seriously so he can get the best out of each day and we can enjoy our time with him. When he does not sleep enough he is not happy. And neither are we. We see no need to drag him out to dinner when he should be sleeping...