You never look a gift horse in the mouth...I am constantly amazed at the glitches that price programs in retail chain computers come up with. It is more expensive in EE & IT time to fix some things... but If it's in my favor on a single item and all the rest of the similar product are correctly priced then the mistake is on the Retailer, and I'll say a quiet prayer of thanks, and put some xtra $'s in the Charity baskets that I regularly support. My turn to need those baskets may come someday, and I like to pay "foundlings" forward a little.
OTOH I try at all costs to be an informed consumer,and know the differences on what things cost to keep from getting ripped off....or recognize the unplanned opportunity.
"These are the times that try men's soul's"...Thomas Paine
"Those who fail to learn from History are doomed to repeat it" ....Santayana
"There's a sucker born every minute" P.T. Barnum, on why he always had customers to see the sideshow features.