Ever wonder what is on your magnetic key card?
There has always been a question hanging over the hotel key cards and the usual answer that is given to the question is that the cards contain the following information:
a. Customer’s name
b. Customer’s partial home address
c. Hotel room number
d. Check-in date and out dates
e. Customer’s credit card number and expiration date!

There is, however, some debate among industry experts over whether some older systems could have been configured to store personal information under specific scenarios.  But it is concluded that this is unlikely

The idea that when you turn the card in to the front desk your personal information is there for any employee to access by simply scanning the card in the hotel scanner is unlikely.  An employee could simply access the hotel computer and pull this information if they were that way inclined.