No. Not as a given. If you really want to, sure, but in real life, if you can’t get a sitter, you don’t go.
I guess that may have sounded a bit harsh, but this new trend of catering to the guests’ every potential whim (food preferences! Alcohol or not, which will be least criticize$? But what if my friends don’t like the idea of a childfree event?) seems way over the top. If you have an evening cocktail or dinner party, do you provide childcare?
It’s a lovely gesture to do that, but unless theirs a boatload of money floating around, it seems a ridiculous extra expense..