That is the exact same rules we have - no company, no going anywhere (off the property, except to walk to the pool when my mom isn't available to come to town and drive them) unless an adult is home. Our boys are 17, 15 and 14 so I don't worry about being turned in for that. They aren't allowed to "take a walk" with their girlfriends (15 and 17 year old) unless one of us is home, or if the girls parents are home and have called us first.
Of course the boys think we are way too strict, but our motto is "If we don't know where you are and what you are doing, then we cannot protect you when the cops come to the door".
So, it's not about not wanting them to enjoy the outdoors, it's about making sure there is never a reason for them to be accused of anything. And that's the saddest thing of all. No longer are the days when kids could be kids - wrestle around, explore, mouth off to each other without the fear of being hauled off to juevenile home.
I find those last three posts very depressing. Obviously, you are conscientious parents, and that is commendable. But remember what the goal of parenting is. You are guiding the development of soon-to-be self-reliant adults with good judgement to go out in the world and make their way on their own. Where in the world do you live that you are afraid that someone will sue you over the behavior of your offspring? Is the only way to avoid that holing up at home? doesn't seem like a workable strategy to me, long term. Now, teaching children to respect the property of others does make sense to me.