I've been to a specific restaurant that has (for most transactions) been rounding up or down for the past few years even though the penny was still being minted. The only issue was that it was inconsistently rounded. And more recently I have received pennies as change or I was able to use my pennies there for purchases.
But the oddball thing is that previously, their prices were "all inclusive" with sales tax factored into the purchase price, where they would figure out what went to sales taxes depending on overall receipts. So all prices ended in at least a five cent (typically 25 cent) increments anyways to the point where they rarely dealt with pennies unless the customer insisted on paying with a few. They only switched to a tax added basis when their prices started to increase and they wanted to keep a lower price on the menu. Even their beverage prices were figured with the CRV and sales tax already figured in.