My kids are "big" now, so this post is mainly on behalf of mommies with little ones.
There should be a law that if a restaurant has high chairs, they must also have kid-friendly food on the menu. Grilled cheese (who can't make that? come on!), mac-n-cheese, chicken nuggets or strips... something little ones can eat.
And pardon me, but if the restaurant serves breakfast and lunch, it's simply not "uppity" enough to get by without having a kids' menu. Period.