Drawing the Line

We have a neighbor girl (about a year older than Lauren and two years younger than Sarah) who frequently comes over to play with Sarah. She only plays with Lauren because she "has" to. To give her credit, sometimes she is nice and encouraging to Lauren, and Lauren has more than her share of the whines. But she's frequently bratty & manipulative. She threatens to go home, or not be friends any more, and pouts when she doesn't get her way.

I'm torn between how much involvement I should have. I'm a firm believer in letting kids work stuff out themselves, without a lot of "fixing" from parents. In spite of that, I tend to remind her (and sometimes the other kids who come over to play) that they have to play nicely. Heh, Jeff is more likely to just kick her out. He has a lot less patience for her.

Once it warms up this summer, I anticipate more activity over here. I got this yesterday:
I'm picturing myself, sitting on the back porch (with a book, probably) every time we have kids over, insisting that they play decently. I'm torn between letting them deal with it themselves or saying "No Brattiness Allowed." Do I want to be the neighborhood hard ass, the Enforcer? Yeah, I'm already on my way to that--last week, I had to say, "No back flips from the top of the fence, guys."