If stores incorrectly post a low price for an item, is it OK to make them honor it?

Dear Mr. Lileks: If a store posts the wrong price for an item, is it ethically permissible to make them honor it? Signed, "Unable to draw from my own set of core beliefs and thus reduced to asking an unqualified newspaper columnist."

Dear Unable: First of all, I don't know why you're asking me, although I sense there might be an insult in there someplace. But since you asked, it depends.

A lot of people think a store's mistake should be binding, but it only works one way. If the cooler has a $24.99 price tag on filet mignon, and it beeps at a buck-fifty, do you think "I'd best call the self-serve monitor over"? If you do, good. You will not have to answer for that at the Pearly Gates.

But if it works in the other direction, suddenly we're all truth-in-advertising zealots. Odd you mention this, Dear Unable, because this happened to me the other day. At the grocery store the cooler sign said that the 16-ounce "sides" for Kevin's Sous-Vide paleo-whatevers were $4.99, purportedly a savings of four whole American dollars.

Nine dollar sides? Nine dollars for mashed sweet potatoes? The ghost of my father appears and whispers in my ear, "That was my weekly wage in 1941 when they sent me to work on the neighbor's farm because Pa came down with the Wasting Croup and couldn't do his shifts at the asbestos factory."

I didn't need that reminder. I won't even pay $5 for pre-creamed yams. It's not that I'm cheap — well, I am, but I can mash my own. Consequently, I live a mostly yam-free existence.

Anyway, I thought the price was suspicious. The sign specifically said "sides," and the items in the cooler were not sides. They were full-on entrees, which usually go for $12.99. But they, too, were 16 ounces.

I looked in the back of the cooler shelf to see if the sides had been shoved to the rear, which I suppose would make them "behinds," but there weren't any. I took two entrees and prepared for battle.

Anticipating a checkout kerfuffle, I took pictures on my phone.

They beeped at full price. I waved over the self-checkout sentry, and noted the situation. I showed him the pictures, which showed without doubt that the cooler was devoid of sides. I'd even shot it wide-angle in case he thought I was cropping out a bounty of discounted sides. He agreed that this was an error, and offered the entrees at the sale price.

Would you have bought them? I did not. When I've described this situation to other people, I get two responses, not including, "Could you repeat that, I lost interest about four minutes ago, around the whole yam thing."

Response No. 1: That was the ethical thing to do, and if you weren't preening about it as if expecting a dove to alight on your forehead with a canonization notice in its beak, I'd be more impressed.

Response No. 2: You're an idiot. The store made a mistake, and you should've held them to the price on the sign. Do you think the clerk was impressed? That he cared? That he watched you leave the store like you were Clint Eastwood in an old western, mysterious man of honor and purpose who'd taught us all a lesson by rejecting an erroneous discount on sous-vide chicken?

Granted, it's not a big moral issue. But I knew it was an error, because of the word "sides." I knew it was wrong, and frankly I'd like to reserve my moments of transparent self-justification for things that matter more. Was I correct?

Wait a minute, why am I asking you? I'm the unqualified newspaper columnist.