IANAL, so if you say exclusivity would be unenforceable, you might be right. But it's not really crucial- the only important thing is collecting useful data, and there are myriad ways to do that.

You'll have to tell me how consumers would game the system. Declaring it doesn't make it so. I've thought on this idea for over three years- I could have missed something, but if I haven't seen it by now, I need someone else to point it out for me.

Retailers might lose control over the "perceived" value, but if they are making higher profits, what do they care? Bear in mind, retailers already have many ways they try to take advantage of the pricing spectrum, they're just really inefficient, by and large.