Sorry for the confusion guys. Here is what the BC Parks web site says:
Payment of Fees Check-in and Check-out Times
First-come, first-served campsites.
If arriving at the park on a first-come, first-serve basis, payment can only be made in cash. No personal cheques, bank debit or credit cards are accepted. Canadian currency is preferred.
In most parks, the park facility operator collects camping fees at campsites.
Several of the travel guides say to bring cash in case the bank card machines are down. This corresponds with what others are saying on this site. No one has said anything about the Canadian exchange rate. I just Goggled it and it is one Canadian dollar = .79 US dollar. I think I will stop at the first bank I come to after crossing the border. This will help offset the fee my bank charges for using their bank cards out of the US.