I think people are generally more concerned about damage than they need to be. I'm a terrible mountain biker and have crashed enough that the BB7 mechanical discs and Magura Marta hydraulic discs on my two mountain bikes should have been completely destroyed by now... if they were as fragile as people in the Touring forum seem to expect. Best I could do was put a slight bend in one of the brake discs, which I was able to bend back by hand. Wish the Avid Shorty cantilever back brake on my touring bike was so reliable! That piece of junk always seems to need attention... Luckily, I have a sweet BB7 on the front!