Personally, I will never cause someone to not enjoy the full experience of the game. If they want to watch the cut scenes, I will let them. All of us play this game for different reasons and as a tank, you should respect the will of the party.

Remember though, as a healer you actually control all the power. Now I didn't say anything but sometimes if a tank is being unruly and obnoxious or going on a power trip, its okay to make him sweat a little :P