Imagine sending your kid off for a fun weekend and then watching them come home Sunday morning with an acute elbow injury from an arm bar...
Scouting was dangerous enough without that stuff. You could get lost and even die in any number of unexpected ways. I watched a friend take a full swing of a wood axe to the top of his head. It didn't make any of us stronger or more interested in the outdoors. Plus everybody told us the Eagle Scout looked amazing on a resume when you become an adult, but they didn't mention that it could have the complete opposite effect depending on where you're applying...
Edit: I see the typical pro-danger, pro-learning-through-injury realism-posturing replies, but these quick takes are inappropriate for beginners, which merit-badge-earning scouts definitely are.