For what it is worth I do believe children (especially daredevils) need to be able to explore and test their personal limits. Yes it sucks when they need stiches. But, they learned a huge lesson about what they can and cannot handle on their own and they will hopefully take that into consideration when they next try to attempt such a thing. As our motto was in a daycare I used to work with..."Children can't learn to balance unless they are put in an unbalanced environment" we used to bring all the toddlers to a huge (HUGE) grass hill by the daycare and let them try and figure out how to get up and down. It was a suitable challenge that gave them tons of feedback about how to manage their bodies. They fell, tumbled and got bumps along the way but in time they learned better balance. Sometimes kids need to fall and get hurt to know how to not fall next time! Try not to be too nervous about them climbing!!
Of course, use reason and common sense too lol.