You're right. I just checked his creature file, and Frostbrand is in his amulet slot! It is still a bug (in the engine), because items that are equipped are not supposed to be steal-able. Drizzt has his very own character animation for his dual wielding, so they really should have either put Frostbrand in his inventory, or put 'Defender' in his shield slot (for the AC boost) and Frostbrand in his sword hand. Go figure...

I have always wondered if the developers do that kind of thing on purpose. I guess it's kind of an "easter egg" type of thing? Like, "if you're willing to try it, or just blindly stumble into it, we put some hidden surprises in the game for you" type of thing. Seems many games have these things in them somewhere, and once discovered, they become time-honored exploits.

I don't see this as a hidden surprise. If the sword is pickpocket-able from the amulet slot, it would be just as pickpocket-able from the inventory. That is if the sword was meant to be pickpocket-able in the first place.

After some testing, I have a list of things you can pickpocket:

general inventory (obviously)
equipped rings
equipped amulet
quiver slots
quick item slots
quick weapon slots (except the one actively in hand)

I'm still not sure this is a bug. Rings and amulets would be difficult but not impossible for a skilled thief (in D&D at least). Whoever decided to put his sword in the amulet slot may not have been aware of this however.

I read that they prevented you to be able to pickpocket that sword in BG:EE version 1.3. People are complaining about it.

Well they put it in his other hand so he can dual wield properly. That isn't a valid pickpocket slot so no more stealing it.

Last playthru: Have Imoen focus on the trap stuff, and then have Alora handle stealth and pickpocketing. Worked perfectly.