I can imagine!
I asked a Publix (or Harris Teeter?) cashier how it worked there. She said that for produce, you do have to buy the number in the ad to get the discount, but not for the rest of the store. I checked my receipt, and it was true (for that store.)
If you’re going to sell a bag of chips for $2.50, just mark the dang things $2.50. Or add a “minimum purchase of 2” to the shelf label.
There’s still a lot of deliberate misleading of consumers. For instance, a lot of sale shelf tags somehow omit the price per unit. Or they jumble the units ( some are cost per ounce, and other similar products are cost per pound.) A bit of clarity in advertising and labeling would be welcome!