When I heal I don't do it. It's just really not necessary, if the tank is good enough to handle the mobs that might stray from him, he's probably good enough at his job that he doesn't need the tick of Regen.
I also don't like running the risk of getting smacked in the face by a mob.
When I tank and a healer does it, I just click it off, I don't make a big thing about it because it's not worth the backlash as most players don't like constructive criticism. :/ But that's just me.