I worked in a grocery store for 9 years and while I'm not saying this is universal, I will say that at least in my neck of the woods any product that is sold by weight but has packaging has a built in "tear weight" (sorry, not sure on the spelling) when you enter the code for whatever product you are purchasing...so that when you enter the code for cherries the scale automatically adjusts for the programmed weight of the package they are sold in. The same is true for the salad bar...you are not actually being charged for the container.