Interesting thread. Thank you to all for informative posts. A few months ago I was staying at a Howard Johnsons in Albuquerque and when I returned from dinner my card no longer worked. After some bungling and a visit from maintenence...they changed out 4 AA batteries in the lock and hooked a little machine up to it and gave me a new key and it was fine.

It was a PITA to be locked out of my room for a half hour though...kudos to those who change the batteries regularly!