I have, however, done it before, and I suspect I was correct to do so. I do, however, try to avoid it unless the gamestate implies that it's necessary.
I agree that looking townie as scum is relatively unimportant as scum skills go, especially if you're doing it at the cost of making your partners easier to find. (This ties into not bussing, fwiw; bussing generally makes you look townier but the cost to your team is rarely worth it.)
OTOH, bussing in the sense of making people believe you're
trying
to get your partners lynched, without actually succeeding in doing so, is a great scum tactic that should be used more often. (This used to be called "distancing" but the terminology got blurred at some point.) The ideal is to genuinely try to get them lynched, in the knowledge that you're sufficiently bad at persuasion that you will almost certainly fail.