hmm, that could work.
The skill level would have to vary depending on how skilled the thief is. Cause a set skill level at which thieves could rob from you wouldn\'t make sense. Just imagine you yourself, as a thief, still being a newbie. And the only ppl you could rob from are like ten skill levels (for lack of a better term) higher then you. That wouldn\'t be fair, and you would never be able to advance in that skill.
So if you would make the skill level vary, and you still don\'t want newbies to fall prey to thieves. Then you should make it so that newbie thieves could never steal from other newbies, thus making it very hard for a newbie thief to steal (atleast in the beginning) and advance. This could be a good or bad thing, depending on how you look at it. (less ppl would want to be a thief, since it\'s so hard. Thus making it more rewarding for those who do succeed.)
And if you follow this thru, a really advanced thief could never pickpocket someone who would be a real easy target for him, since the skill level at which he can rob from ppl has also moved up a notch. Thus making it always a challenge, and less annoying for the other ppl in the game.