The player cards are using the multi-point contact, which is a memory chip! That means that the card itself holds content (data). Most likely your play, but most often your profile info, i.e., whatever information you gave them to sign-up.

The danger is... that personal information can be read by any multi-point contact reader, unless of course the casino signed up for encryption as one of the add-on features to such tracking systems. Unless it was a free add-on, don't copunt on it being there!

Jim