The only risk magnetic key cards pose is that they're easy to hack to gain access to a room.
Worked for a multinational company and security division always cautioned us to not leave the room key card behind in the US or abroad. Instead take it with you when you leave and destroy it later. They said the cards contained personal and credit card information that did not need to fall into the wrong hands.
This^^^^^^
That is an old wive's tale.
Well I don't have a 'old wive', so what's your point?
