For metas, what about just writing a quick macro that has one of the pets say "Sorry, Boss is busy." Most of us would understand and get a kick out of it.
Or with those great big floating billboards of yours, Metas willing to buff while in civilisation might change pet names to something like "BuffingMasteries"? We might learn to not annoy those who are busy doing other stuff?
Still think Agents should get a "Hide Prof" or False Profession: Other - "Not Buffing" that shows up on char info.