Hola
@Irenie !
If it's any comfort to you, here in Spain people give out their personal ID numbers *all* the time (to the post office when picking up a package, to the schools when signing something for the kids, to deliverymen, when signing up for Carrefour loyalty cards, etc.). It's not like in the US where we protect our driver's license numbers and our passport numbers since others can steal them to steal our identities. In Spain, it's children's faces and personal beliefs (creeds, religious beliefs, membership in organizations) that are under a higher level of data protection than "simple" information like ID numbers, addresses, and phone numbers. When we registered Pilgrim House for the agency of data protection (saying we would comply with the data protection rules) we learned waaay more than we ever imagined we would about the way things work here - it was fascinating.
All that to say - it's still good to be cautious and wise, but it may not have occurred to your good Samaritan to do anything bad with your card. Hope that helps lessen any anxiety
. Take care!
Faith