I was not aware of this before and didn't notice it mentioned here, but apparently there is a certain level of customization of the PC membership card that allows you to put several of your other membership numbers on it for convenience. I never carry any of the cards with me, but for those that do, I think this is a nice option. https://secure.priorityclub.com/rewards/us/en/account/customizeCard "We know there are other loyalty programs out there, and as a savvy traveler you probably belong to a number of them. But wouldn't it be nice if you didn't have all of those membership cards filling up your wallet?Priority Club Rewards is pleased to offer you the ability to keep all of your membership numbers in one place. Whether it's your frequent flyer programs, your car rental membership or another hotel loyalty program, you can now include all of this information on the back of your Priority Club Rewards card."