When I was tanking, I never saw this as an issue. When I heal now, I do try to be mindful of it, but not because I can't but because many tanks play in a manner that prohibits it. But my view is this :

If you haven't hit them with any skills, you haven't pulled you just ran into a room full of mobs. If you hit them with a skill this isn't an issue. When I pull I am always tabbing and dropping an overpower/flash or tomahawk/shield lob at stragglers. With practice you can do so without stopping and it just makes the run easier to deal with as everyone can do whatever it is they need to do whenever they need to.