Ah, interesting point, I hadn't considered that. It seems like that would take away a lot of the power of electronic price tags though. You raise the price on the price tag and people take the product at the new price, indicating they're willing to pay that new price, but you still charge them the old price.
The real holy grail in price segmentation would be something like Google glasses that show individualized prices for each product. Then the store could do all kinds of targeted price promotion based on my buying history. Or even do promotional pricing based on my shopping trip for that day. Maybe it notices I'm about to checkout and I have hamburgers in my cart, it could offer me a promotional price on buns. Or lower the price of sale items as I walk past them without picking them up to try to find the highest pricepoint I'm willing to pay.
The real holy grail in price segmentation would be something like Google glasses that show individualized prices for each product. Then the store could do all kinds of targeted price promotion based on my buying history. Or even do promotional pricing based on my shopping trip for that day. Maybe it notices I'm about to checkout and I have hamburgers in my cart, it could offer me a promotional price on buns. Or lower the price of sale items as I walk past them without picking them up to try to find the highest pricepoint I'm willing to pay.