We've had a blue and white paper card listed in the guides from the Grand Casino Biloxi - a Grand Advantage Players Club card where you could record your account number with details on the back. The originally listed card had the small numbers 8699 in the back right bottom corner.

I just came across a similar card that is formatted slightly different and has the small numbers 3059C in the back right bottom corner.

Here's scans of the originally listed card and the new found card.