A big change is afoot at Walmart, and some shoppers are starting to notice. It all comes down to one of the smallest (but most important) features of any store: price tags. The retail giant's adoption of so-called digital shelf labels in place of traditional paper ones is causing a bit of confusion and concern about whether shoppers will get a fair deal. Several lawmakers have filed bills to prevent the tech from being used for surveillance pricing or surge charging. A proposal in New York