I was in Las Vegas this past week for Interop, where I stayed at the Luxor with the other Interop Labs team members. The Luxor has a “security” system for guests which requires that you have a valid key card to use the elevators to go up to the guest rooms. The system is only marginally better than the “show a key card at the elevator bank” system that other hotels use.
You see, every key card unlocks every floor. I was on the seventh floor, but the elevator didn’t require a key from the seventh floor to enable a stop on the seventh floor. If you want to get on to any floor, just get on the elevator with somebody else and wait for them to “unlock” the elevator before you press the button for your desired floor. (If you’re lazy like me, you can also let other passengers unlock the elevator buttons before you hit the button for your floor, too.)