The big chains that do this in Europe are very clear that prices never go up during the day, and generally everything bulk updates at night. Baked goods get cheaper towards the end of the day, for example. The linked Planet Money episode in the article covers it nicely.
But sure, once you enable the capability, it won't be long before we are living in the inevitable grim meathook future.
But sure, once you enable the capability, it won't be long before we are living in the inevitable grim meathook future.