I think it's a nice idea too, I don't see why you'd need a permit, don't people do picnics at US parks all the time?
OTOH I don't know how you guys do it...meeting people this way that is. How do you know that the kids/moms that will show up are actually people you have something in common with, that you'll like them and want to spend more time with them? I mean, if you're the one inviting then you're sort of on the spot. If a mom decided she wants to befriend you and you decide she's really not your type how do you avoid her after this. It is you who made the first step, how do you back off? It is totally different if you meet in neutral ground (say a neighborhood event) and if you click together you exchange numbers etc.
Don't get me wrong, I know you guys network in different ways than we do here (perhaps we don't network?)...so I'm just curious how things work out so well. I would never dare do it for fear I'll end up hanging out with a group I can't stand. I'm pretty picky that way.
I do know though that it was much easier to befriend neighbors in Chicago than I ever did in Athens. In my building there were fun people, of similar age/interests/hobbies, similar education etc...No families in my building. But that's because a lot of young people live on their own there whereas in Greece they mostly live with their families. Anywhere I look around me here is families, completely different in composition. I guess the fact that we all live mostly in apartment buildings makes things more impersonal too. My old neighborhood was more of a hood, two story homes etc...and yet I really didn't like/care to get to know anyone or their kids better.
Anyway, I guess I got carried away in my thoughts...It just interests me how things work in different culture and why is it that some things wouldn't work here the same way.