Barclaycards often have terms that if you do not use the card or have some kind of balance every six months you can be excluded from earning rewards in the future and forfeiture of existing points, this from the Priceline Visa terms:
Effective on September 10, 2010, to continue to participate in the rewards program, your account must remain open and in good standing, you must maintain your creditworthiness and you must use your card for at least one (1) purchase transaction every six (6) months (or have some type of account balance every six months). Failure to meet these requirements may result in account closure and/or forfeiture of all outstanding points earned. In addition, if your payment is late in a particular billing cycle, this may result in the forfeiture of points earned in that billing cycle. If your points are forfeited for any reason, we will not reinstate these points to your account.
Points that have already moved to other programs, like an airline or hotel card would be safe, but those in Barclaycard managed programs like Priceline could be at risk.