The
DVC member would have had to pay for the dining plan when it was added to the reservation, unless this reservation was booked before that change occured (around Mid-October, 2010 I believe). Before the change you could wait and pay for it at check-in but it depends on whether they booked the reservation before they started requiring pre-payment. It has to be added at least 48 hours prior to arrival, you can't add it at check-in.