That's when you tell him that you don't accept the authority of someone ignorant enough not to know most of those kids live with, gasp, males, to make or enforce rules of any kind.
Unfortunately it is a very good playgroup otherwise, and easy walking distance for the kids.
The group leader just takes her responsibility seriously - there was a sex abuse case last year in the other local playgroup, which was forced to close.
I just go down with a neighbor, and she brings mine out with hers.