Thief 2 has known bug which causes game statistics always to show one more pickpocket than actually present in a mission. As was discovered that extra one is Contains link from bowman (-547) to QuivArrow (-121). Also bowman (-547) archetype has property Engine Features>Inherit Contains set to True. This was done in order each time a concrete bowman is added to a mission, he had an arrow in his quiver. If in the mentioned link to change data from Alternate to Generic Contents then it won’t be counted as pickpocket and statistics will show the right number of actual pickpockets.