I wonder if that only applies to a Sim that you are playing? The reason I ask is because I saw a game-generated townie kid swipe two things off of counters in a diner - not one right after the other but about a Sim hour apart. The diner was "Goldie's Griddle" created by Jenba. I had to look at the pictures of the diner that she posted on her Tumblr to see what the little rat took.
I also wonder how big an item can be for a kleptomaniac to steal it. The reason I ask that question is because the other night I was testing a large park on the Twin Oracle lot in Newcrest. It had three fountains of various sizes. The smallest fountain was by some harvestable trees and plants, a medium sized fountain was by some chess tables and a huge fountain was at the entrance of the park. When my Sim arrived at the park I checked the plants, looked at the spacing of chess tables, checked the placement of lights and easels - everything was fine. As the Sim was getting ready to leave a few hours later, I noticed that the smallest fountain was gone. I think somebody stole it.
Needless to say I am deleting any Sim that the game spawns with the Kleptomaniac trait.