My DS and DD play outside either on their own or with two from next door quite happily for hours on end, without too much trouble (not saying they're perfect, but I can get on with stuff in the house without having to keep a constant eye out and if there's any trouble one of them will usually come and tell me). There are two brothers in the road who were never let out until last summer - not even playing on their front garden (they are nearly 8 and nearly 5). Now they seem to be left to play out with no-one keeping an eye and it seems the minute they come out all hell breaks loose. Last week we were eating dinner when we noticed they were in our back garden (having come through a shut gate). We told them to clear off, but this leaves us worried about going out or on hols. Our garden has a greenhouse and a shed full of tools/hedge trimmer etc, so we generally don't let many other kids in the back unless we're there. The other thing is that children seem to have very short memories so they forget that last time they got into a big fight or a load of silliness which got out of hand and just go and play with them anyway. It's very difficult to say 'Don't play with x and y' when we only live in a small road. Any advice?