They're going to dynamically price themselves out of a number of markets with this approach.

Unpredictable and inconsistent pricing has already cost a number of grocery chains a lot of business to Costco where prices can remain the same for very long periods. I've personally abandoned a number of businesses for shifting prices around like a shell game, and I deeply resent what should be a predictable purchase being made to feel like a grifter's bazaar or financial markets.

As if a new reason to bypass McDonalds was really needed.