Probably from when Priority Club goofed and deposited points for opening a new PC credit card for everyone who participated in their Crack the Case promo, along with the related bonus points for cracking additional latches even though people didn't earn the points. PC corrected it without warning and pulled the points from everyone's accounts. However, some people redeemed the points on free night reservations, and IIRC, PC allowed those people to keep the reservations, but sent their accounts to a negative balance.