I've seen some backlash where folks would abandon cart at the till, or ask to remove the item and leave it there at least, causing quite some chaos/delays overall. And that's just user error/misreading a label. Pretty sure if pricing is unpredictable between displays and the till often enough, people will just go shop elsewhere and/or regulation would eventually be created if it doesn't already exist...

The other thing is for folks who can afford to pay more, I'm not sure they even look at the prices on the shelves. I assume they may rather look at the end total and only check individual items if the end bill is abnormally high, in which case if everything was upped a little based on profiling, it might not be noticed unless googled or compared to another store?

I guess those behaviours may not be correlated to income, but all in all I have a hard time imagining this system resulting in either tiny optimizations that may be profitable in agregate or a net loss of clients/sales if it is too noticeable...

in some countries maybe, I think in some US states? I don't think that is standard though.

This scenario is easily avoided though, change prices once per day, or you could change prices when the store or aisle is empty.

this example is trivially solvable