Depending on the jurisdiction, price tags also have to be correct as well.

In certain areas, the consumer laws are such that the lowest of the register price and the displayed price must be used, and in other even friendlier jurisdictions, a discount of $10 has to be applied to the shelf price if the shelf price is lower than the register price (including giving away the item for free if the item is worth less than $10).

In those jurisdictions, ensuring that the price is correctly synchronized between displays and the registers is significantly more important than in jurisdictions with weaker consumer laws.