Why don't we go a step further and say that proper etiquette should be to always rappel when cleaning? I never lower off hardware unless for some reason I have to. I didn't pay for that hardware at the top. So what gives me the right to slowly saw a hole through it?
Not sure what other reason the FA team would put in $40 mussy hook, other than so people can lower from them. They do get replaced quite often. I do agree people need to use their own draws when doing TR laps, I've run into some pretty worn draws at ORG. I'm surprised there hasn't been more accidents.
Let me just say, as someone who lives in Bishop, I would much rather replace a couple of mussy's, than carry out someone who is injured or dead. Everything wears out eventually, so one of the reasons we've adopted the mussy system is that they're much easier to replace when they need it. If you're going to run toprope laps on a route, please use your own draws. However, if you are the last one on the route, or cleaning on the way down, by all means clip in and lower off the hooks. It's faster and SAFER.