I'm sure there will be many who will be offended, just as there are if you wear a blue jumper to a tournament or stalemate them from a losing position.
Use them if it speeds up the game, I use them a lot, nobody has ever complained, and I don't feel insulted if someone uses them against me.
TSMIMITW is right. For most players here, cm's are fine.
But I would add one caveat. CM'ing one to mate is not good form, unless they are moving with one minute to play-repeatedly-in a clearly lost game.
I have conditional moved to self mate before, my opponent thanked me.
haha!
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