I never worry about such things. I have this huge cottonwood tree in my from yard and when I first moved in a few neighborhood kids rang my doorbell and asked if they could climb it, because it was the 'best climbing tree anywhere' - LOL. I thought that was cool, especially since they made it a point to ask ... and told them that as long as their parents were okay with it, it was fine with me. It's kinda neat being an old guy hearing the kids out front from time to time having a good old fashioned ball climbing that tree. Plus I didn't get a grumpy old man reputation, even though I was only in my fifties or so then.