I offended a tank in tam tara normal by going ahead as a MCH. Sprout healer was even onboard. Before we even got to the first... boss? if it can even be called that, they then ate a 30 minute penalty and I guess the arcanist left after the tank did.
Got replacements easily but hoo boy people need to touch grass. Almost demonstrated how painfully easy it is to do an early dungeon with an aoe-capable dps and a conjurer. Their loss since I got out of the duty not even 1/3 into their penalty. Remember boys and girls (and robots) that by refusing to tank you're technically griefing the party even if your presence is optional! I've opened that can of worms, not sorry.