Gavin, Mikey and even Sean (and previously Ethan) take every opportunity to scale things, climb things and balance on objects that beckon them to balance on. While other mother's are yelling at their kids to get down, I'm taking photos.
Gavin & Mikey are particularly agile, and I like to think some of it is because they have been allowed to hone their skills. As far as tightroping walking goes, they can do the tops of bike racks, chain link fences, the tops of swingsets, and railings.
I particularly like that they did this with books in their hands, looked like they were walking on the ground and turned around at one end and did it again without falling.
Hey, you have to start somewhere!
Dangerous? We haven't had any problems yet. I guess you risk a broken bone, but I supposed that's bound to happen sometime.