I have to say, unless you've had a child immobilized by a break for 10 weeks, as we did when DD broke a leg bone on a tramp, you don't know what an enormous pain in the butt it is for everyone. DD even lost friends at school because she had to sit on the sidelines on recess. No PE--she had to sit in the library. It was pretty hard on her. Had it been at a different time of year, we would have had to cancel our vacation. She also fractured her growth plate, which can lead to long-term problems. A broken bone isn't the worst thing ever, but let's not take them lightly. It also cost us close to $1000 out of pocket. Fortunately, she did not need PT.
as for this:
There are a ton of folks with tramps in our circle and I have NEVER seen even ONE person make the kids go one at a time. This is my problem--after our experience I want to make a rule that my kids can only go on one solo, but there is no way to enforce that at a gathering or playgroup without being That Parent.