We always pay cash since we never pay more than 2 nights at a time. That's good insurance against paying for several nights and then having to leave for some reason, since there is no refund. We make a point of keeping a stash of small bills in order to have the exact amount available.
I dislike writing checks that give everyone my home address, phone, & bank routing/account numbers. That's just one more opportunity for rip-off.
We've never had an issue with anyone trying to say we didn't pay. You have no proof you left a check either, until it clears, which may be several days or even longer. I'm sure the hosts/rangers at these remote campgrounds don't run to the bank every day.