No one's ever gremlin bombed for the XP - it's the items. I have gremlin bombed in the graveyard, and got insane amounts of loot even just killing the gremlins with my own hands. (As you might be aware, I don't think a great deal of pickpocketing.) My point is, essentially, that the problem of gremlin bombing isn't a Pick Pockets problem. Yes, they get more dangerous as you kill more, but a) you can use pets no problem and b) you get insane loot long before the gremlins become remotely dangerous.