Where I live (Poland), prices on shelves are displayed in full (more than that, there's the price you'll pay for an item and price per unit of mass/volume, to enable comparisons), but on the receipt, there's always a per-product sales tax summary printed. So if I cared about sales tax revisions, I could easily notice it on the receipt. But most of the time, I just learn about revisions from a news article.
Where I live (Poland), prices on shelves are displayed in full (more than that, there's the price you'll pay for an item and price per unit of mass/volume, to enable comparisons), but on the receipt, there's always a per-product sales tax summary printed. So if I cared about sales tax revisions, I could easily notice it on the receipt. But most of the time, I just learn about revisions from a news article.