In the last 3 days, I have had kids in my yard.
Two nights ago, I was walking into the bathroom when I heard a voice outside. The kid from the house behind mine was trying to corral his dog. They ended up walking all over my lawn. I hope I escaped dog crap. There's nothing worse than not owning a dog and still having to clean up its crap. At least this appearance in my yard wasn't intentional as it looks like the dog got away from the kid.
Last night I found kids in my driveway when I arrived home. I believe they were playing with my hose because the area beneath it was wet and had not been wet when I left the house to go get gas. They saw me coming and somewhat reluctantly and slowly moved out of my driveway and went 3 doors down to drive up someone else's driveway. Later last night, as I sat on the deck resting, a kid came to the back edge of my property, crossed the ditch, and walked his bike across my back lawn, onto my driveway, and up the street.
Tonight, I was home watching TV and heard voices near the house. I live alone, and hearing strange voices nearby on the outside of my house scares me. I looked outside and saw a second kid driving his bike over my lawn -- my $5000 lawn that I am trying desperately to keep in good shape in its tender growing stage. There are still areas, particularly in the front, where the grass is just beginning to take root. I ran to the door and firmly but not yelling told him to not drive on the grass, and told them to go play somewhere else.
Apparently my yard has become the neighborhood playground. It is also apparent that their parents haven't taught them to stay out of other people's yards. If I want kids driving over my lawn, I'll get some of my own. In the meantime, don't scare the crap out of me by going right up to my porch and going under it or whatever the heck they were doing.
This is my property. I pay for it, I maintain it, and I decide what happens on it. It doesn't include being an entertainment area/transportation path for uninvited children. You have your own yard and yards of friends. Go play on those and leave mine alone.