Our boys are no longer allowed to go over to a friends after something their friend's dad pulled last week.
bg: We live about 3 blocks from our very pretty city park that has been there since the 1800's and is very nicely kept, with a lovely large pond, an art museum and gallery at different ends of the park, etc. There is a wide field that has two baseball fields and backs up to train tracks. Bikes aren't even allowed in the park, or skateboards, and their friend's dad took them and his son over there in a 4 wheeler.
Someone apparently called the police to get the guy to leave so he did, leaving our sons (11 and 10) behind at the park by themselves. Thankfully they're old enough to be there by themselves and can safely get home on their own, which they did. And even if they weren't, my oldest has a cell phone and could have called DH to come get them (I was out for a few hours while this was happening). Pirateboy2 told me he and his brother had gone somewhere (to the bathroom I think, though the park locks the bathrooms in the winter but they always forget that) and when they came back, the guy and his son were gone. Didn't even make an attempt of any sort to let the boys know he had to leave. (and they do have Pirateboy 1's phone number)
Their friend is allowed to come over and play at our house but in showing bad judgement and being a SS, we don't trust the dad to make good decisions with our kids around.