I'm sure this is something that Keith Richards once said: "Nothing terrifies me more than losing my hands. I wouldn't be able to do what I love anymore. Drugs." Of course, the joke there being that he should be more terrified that he wouldn't be able to play guitar anymore, not that he wouldn't be able to do drugs. It's at least five times funnier when I say it in his accent.
Keith Richards probably gets paid a hundred thousand dollars just for strumming the guitar once. I play a whole song and people pay me to leave. That's not money you want to lose out on if some rude dude comes by and chops your hands off. Great business decision for Keith. Someone else can put the joint to his lips with a couple of million in his bank account.