Her question involved whether the business had to accept the pennies as payment. This article addresses that question. My sister also wanted to know whether this disorderly conduct thing made sense just for paying in pennies. My guess had been that there was more to the story than just paying in pennies -- and in the event, he was apparently huffy and the pennies weren't wrapped. 2500 pennies -- 2500 of a lot of anything big or small -- can make a real mess.
If you attempt payment on a bill using US currency in the US and the person refuses the payment, it turns out to be really hard to use the court system to go after them for nonpayment. This, of course, is a lot different than the examples included in the article (buses only taking change, places refusing hundreds, etc.), in which the person refuses to _sell_ something to you.