I play sc2/D3/HS all while botting on same WoW Account. Haven't had any issues but always the risk i guess.
I do it, it's not risky at all seeing as how GM's only have power within WoW not all of B.Net I believe.
I run two instances of HB, along with SC2, and usually Hearthstone for my niece all on the same bnet. Also interesting, your bnet friends always show the most recent login. So if you start your HB's then log into sc it'll only show you playing sc to your bnet friends. I like to keep sc running and if I'm afking I just go on away in sc. That way all my realid friends don't see WoW up for hours on end. And you don't disconnect from sc if you leave it open.