I wish they'd say "brimstone" for a Conjurer and "dead things" for a Necromancer, though I doubt that'll happen.
Doesn't seem all that hard to do, tbh. Just record the number of each thing summoned.
Though it could be a nice trait for people to dislike you for Conjuration. Assuming they can smell it on you, I doubt they'd be all too happy with you summoning undead/the evil minions from Oblivion.
And perhaps sneak/security. People may be able to tell that you're a shady character. I know I've saw some of these people in my time.
Of course, they may like you in other ways to cancel out the disposition loss. Be quite happy if this necromancer saves my life/planet, if I'm honest.