Free Trampolines
Trampolines these days are still pretty unsafe, but they're usually at least concealed by a net so a kid won't go bouncing off the side of it. When boomers were little, trampolines did not come with a net. You had to just jump in the center and hope for the best!
Random Friends
It's pretty common for friends to meet through school or around the block, but in these cases, the parents already know each other. Back in the day, if you met a kid your parents didn't know...that was fine and normal! No need to meet the parents, surely they're probably okay...