The real question would be how did the clerk/store handle it when pointed out?
I've never once had a grocery store quibble over a discrepancy - they've always just overrode the price, right then, and went on with their day. At most taking a minute.
Compare that to before there were barcodes, and just price stickers on things (yes, I'm that old). This was a LOT more hassle.
Ever see a sitcom where the clerk is calling for a price check over the intercom? Yep, that's what they used to do. Most of the time we'd tell them nevermind, don't bother, because it took too damn long and there was a line of 3+ filled, large carts behind us...because checkout took forever as the clerk rang in, manually, every item. Pulled out their sheets to verify prices, code, etc.