As some items are more difficult to pickpocket and thus greyed out depending on skill level (a good thing), this can actually break quests as I have discivered (the elf-orc feud quest line cannot be completed if you loose the argument to Victoria and pickpocket the elf for his gold and then have to wait for the second skill point to be skilled enough to steal the bloody amulet).
Hm, I don't think that this is quest breaking. You had the chance to steal the amulet in the first place but you were too greedy. That's your problem. But apart from that there are other ways to solve the quest (convincing her to give you the amulet or killing her)...
