Fat-finger implies you made your mistake once. A UI can't stop you from setting out to do the wrong thing, but it can make it astronomically unlikely to do a different action than the one you intended.

Simple example: I have a git hook which complains at me if I push to master. If I decide "screw you, I want to push to master", it can't assess my decision, but it easily fixes "oops, I thought I was on my branch".