The annoying thing is that the store again has all the power here. If you get overcharged for something that was supposed to be on sale, scans as the wrong item, or the price label is different than the scan, it is on YOU to notice, then wait in line in person to explain the problem and get it corrected.

There is no penalty for the store and you don’t get any additional compensation, so most people will say, “I guess it’s just $2 so it’s not worth fixing.” But suppose this happens to thousands of people. The company always wins.