Both thieves and non-thieves should read what follows, as it applies to all concerned.
Picking the pockets of fellow Player Characters is strictly forbidden, and repeated offenses may result in a permanent ban.
Player Character thieves may attempt to steal from NPCs, as small amounts of gold and other trinkets have been placed on many of the NPCs throughout the world. Keep it in mind that if you are caught, that particular NPC will go hostile. You will have a few seconds to run before they chase and attack you, so you had better get moving. That single NPC will remain hostile for a short while. Also know that if the NPC attacks you, and you kill it, all guards and other defenders in that town will be hostile toward you. In fact, the entire town may be hostile, depending on who you killed. Simply put, choose your NPC mark carefully – it would be foolish to try to pick the pockets of a town guard or other prominent NPC.
You may only steal only one item from any given NPC per server reset. This is to maintain some level of realism; a person who notices something missing would be on high alert for some time thereafter. (But alas, the game cannot code for this, so we must restrict and role-play).