It seems more reasonable than the outright refusal of many businesses to accept cash at all, and plus this transaction isn't even a "debt" to which the penny would be legal tender.

As I understand it, more than X dollars worth of coins is not legal tender. I learned this due to an absurd case in Detroit, where someone stole bags of coins from an armored car, got caught, and claimed their crime was not a felony because it was below the dollar limit for a felony. Of course the judge treated their request with the disdain that it deserved.

There are multiple laws that could have been broken to make it a felony, but if the only reason it would have been a felony was the dollar amount, I'm actually less inclined to side with the judge.

This is all third-hand, through a game of internet-telephone, and my money (if you'll pardon the pun) is on there being additional factors though