Fences are merchants who buy stolen goods. They were introduced in Baldur's Gate II: Shadows of Amn and subsequently backported to the first game in the enhanced edition.
These merchants are listed in the Fences category.
Sell/Steal exploit[]
Some fences also allow stealing their wares, creating a sell/steal loop that generates money infinitely. It is an incredibly repetitive activity and since stealing never has a 100% chance to succeed, it can require reloads on top of that. Money is only a real problem at the start of the game and while it may help gaining some capital early on - it is repetitive and items bought with coin are generally not items that last throughout the game.
Bugs[]
If you sell a fence an item that they already have in stock, it will create two stock entries (one normal, one marked as stolen goods). However, if you then select one of the listings to "buy", it will select both and it is impossible to steal them back (since you can only steal 1 item at a time) or select how many to buy through double-clicking. You will always buy 1 not stolen and 1 stolen until one of the stacks is depleted.
Contributing[]
Fences are automatically added to the category using the store intro template, by setting the fence toggle to yes.