With Shopsite Pro 11 r1, I just got an order which includes Que�bec as part of the address entered by the customer. I am assuming the customer typed Québec, although I don't know that. The customer also appears to be using a Mac.
I see the string Que�bec when I click on "View orders" in the Shopsite dashboard, using Firefox 18 or Internet Explorer 10 on Windows 8. If I click on "View source" in Firefox, I see Qu�bec, so it seems something mis-decoded the original é and converted it to the UTF-8 replacement character, which is used when an invalid codepoint is found.
I notice on the checkout page that charset=ISO-8859-1 is specified in the header. Maybe this would be better as UTF-8?
~ David