the kids don't want to be confined to one room, and i don't want to be running after them monitoring them.
but i also don't want to spend an hour of my time picking up room after room after they leave...i think i just need for the mess to not happen in the first place. a 7 year old should already know better than to trash someone else's house. as should a 5 year old.
If you don't want to confine their play area and also don't want to set up some cleaning guidelines, then things will stay the way they are and you'll be stuck with a massive clean-up after every playdate with this family. Venting here that they're messy is fine, and I'm sure it's frustrating to be faced with a huge mess when they leave, but unless you implement some changes in the way you handle the situation with them, nothing will change.
I know what you mean, and I find myself feeling jealous of friends who have housekeepers too sometimes, but it's not necessarily the root of the problem here. Plenty of my friends with housekeepers are still very conscientious about helping clean up before leaving my house, just like some of my friends who clean their own homes tend to be messy guests when they visit me.