Yeah always. Also in self checkout I stack things on top of each other if I'm getting more than one of something so not only do I get the thing for cheap but I also get one free lmao
this is how i get most of my candy bars. or look slightly frazzled and scan items quickly with two hands but 'dont notice' that one item didnt scan as you put them into the bag at the same time. grocery stores in my area have weighted self-checkouts that can usually sense when an 'unexpected item' is placed in a bag so that dupes it (and the cameras) most of the time.