The customer's receipt absolutely does need to correctly itemize sales taxes. It is an input to the customer's own tax filings. And obviously, overstating the s

The customer's receipt absolutely does need to correctly itemize sales taxes. It is an input to the customer's own tax filings. And obviously, overstating the sales tax is illegal regardless. Any sales tax decrease will not be transferred to the customer except in a delayed fashion under your model. Furthermore, requiring the retailer to eat any downside on sales tax changes will cause average prices to increase, albeit slightly in most cases, to transfer the risk to the customer as happens in every other market where operating costs are not directly chargeable.