Originally Posted by Nephythys
But you're probably going to have to make exceptions anyway. I can hear the 8 month-old's mom saying, "well, our baby can't walk yet, so there is no way he'll fall in the lake as we'll be holding him the whole time..." You might have to concede to that one. They are either going to come with the baby anyway, or not come at all. So it just depends on which battle you want to fight.
That said, you feel free to do whatever you like. The other adults will also have a better time with no children present. It's like when you are flying on a plane and a family comes down the aisle and all you can think is "Please don't sit next to me, please don't sit next to me." Sometimes it works out and everyone has a good flight, sometimes it is miserable. Best to ensure the fun for the greater group if possible.