Use Your Smartphone To Unlock Your Hotel Room

InterContinental is about to start allowing guests to unlock their hotel rooms with smartphones. This way, if you put your hotel magnetic card next to your phone, and as a result the configuration is being deleted (as it always happens to me…) – you don't need to worry! You can still use your phone to unlock the door.

Call me old fashion, but I can easily see issues with this new idea: hackers will open other people's doors, smartphones will run out of battery… who knows what can happen?

I think I will prefer sticking with the good old magnetic cards…

(source)