Originally Posted by
eduskator
No! There is a limit screw
(dumb proof mechanism if you want). Try to downshift when your chain is on the lowest gear - it should be impossible mechanically speaking.
You've never had the limit screw come out of adjustment? Perhaps not if you understand what it does and you are the only one that messes with your own bike.
I had kids that liked to imitate dad and they thought they understood how to adjust their own bikes DR's. The dork disc probably saved me from having to buy them a couple more bikes.