My family is all our of state and has a lot of young children. We also have a number of guests living 100 miles or more away who have little ones.
I'd prefer no kids at all, but I don't think that's a realistic expectation, especially for traveling families. Does it make sense to invite out of town children only? (Thought being that locals will have a much simpler time finding a sitter, leaving whenever they like, etc)? Or to limit the invited children to only kids we know already or are related to? 
Or is this one of those all or nothing deals? I don't mind seeing my Alaskan friend's new baby or my cousin's 2-year-old, but I'm not all that interested in bumping our adult friends for the random offspring of some family acquaintance that our parents want us to include.