Some people just seem to have a natural talent for procuring items which don't belong to them.
Dealing with thief may always end having a little less weight to carry than before.
But as you know the only thief is caught thief, and that is hard to achieve;
thives can sneak unsneen behind your back, find perfect places to hide and quickly picked lock
on a door can often be enough to stop you from following the thief.
Back to classes
Kenders and Hobbits are excellent and Elves and Half-Orcs tend to make very
Giants and Trolls are too big and stupid to have any skill in it and Demons,
Numenoreans and Ghosts are too proud to do it.
Dexterity and Perception are prime statistics for a thief.