Yeh. I make a point to ask if I should turn on growl (my default is off) when I know a spot is particularly difficult. Sometimes, I manually activate it when the tank is about to die, too. But otherwise I try not to interfere in tanking myself.
…please don’t make me play a healer. I’d have to change my entire keyboard setup. 
But a simple “wait for a second, let the tank do his thing” shouldn’t be too hard to grasp imo.