I'm in Miami this week, and just checked into the hotel. And I was reminded of one of my most-hated peeves: when the room's key-card loses its magnetic muster. Then you gotta go to the front desk and beg them for another one.
"Just be sure not to get the card near any other cards, or near a cell phone, or anything that might contain sulfer, or the color green. And don't let the card come in contact with any kind of atmosphere, such as oxygen, or it will stop working immediately. And whatever you do...don't feed it after midnight!"
Can you remember when real keys opened hotel room doors?