Snooping is a required skill for all pvp thieves, it allows for targeted, rather than random, stealing. It is an active, not passive skill. There is no ‘snooping’ skill check when stealing – the only time the skill is checked is when you attempt to open a container belonging to someone other than yourself. The title attributed to the skill is ‘spy’.

Snooping is performed by opening the paperdoll of your target and then double click their backpack while standing within one tile of their location. A skill check is also made when attempting to open any sub-containers within the backpack.

If the attempt is successful you will remain hidden, however a failed snoop will display the message “You notice (name) peeking into your belongings!” to all players in the area and reveal you if you are hidden. Grand Master Spies will never fail to snoop successfully, and therefore will never be revealed by the act.

Although snooping is typically looked upon as a negative act,
you cannot be Guard Wacked for it, nor will you be flagged as a criminal, however it will lower your karma and you can not perform it in Trammel, with one notable exception.

To train the skill in Trammel buy a pack animal and then release it. You can effectively gain by snooping the animal’s pack when it is ‘wild’ rather than ‘tame’. If you also buy a crook from a blacksmith or armorer npc you can use the herding skill to instruct the pack animal to follow you. Elf or Gargoyle characters will need 1.0 skill in herding to do this, human characters have the advantage of their Jack of all Trades racial bonus. Without herding it will be necessary for you to follow the animal wherever it wanders in order to stay within reach of its pack.

To train the skill in Felucca the same procedure is viable, or you can simply wander around any Felucca town opening the paperdolls of the npc residents and snooping their packs. Escort quest npcs are best for this, as they are static. Merchant and other npcs have an annoying tendency to walk away, leaving you with the message ‘I can’t reach that’. Alternatively seek the assistance of a friend, target the friend’s back pack by his feet on his paper doll and just use a ‘last object’ macro to repeat the action.  A gain check will be made for attempt to open it.  You could of course also snoop any player who happens to be in town, but they might suspect your motives, since snooping is most usually followed by stealing.

Unlike stealing, snooping can not be trained using a pack animal set to guard you.

With thanks to Mikni, Krinkle and Fink for additional information.