There is no reason to taunt when you are top threat, unless it magically adds +threat (from all other MMO's it just moves you to the top of the hate list). When raiding in previous MMO's I played either Healers or DPS, and as the above post said I was trying to be humble.
I was in Triton in EQ had multiple world first kills, and as far as hardcore goes..I used to play MMO's 16-20 hours a day before I had to be an adult. Obviously I do Guard my top DPS, but if I am testing things...then I try and check multiple variables. I am mainly talking flashpoints, I haven't had trouble in Ops.