Why can't we have them?

In Asian and European hotels, there is a master switch near the front door of each guest room that is triggered by the insertion of a hotel key--when then key is not in, neither the lights nor air conditioning works.  It allows: (1) to always remember where one put his key and (2) to shut down lots of energy use on departure.

It is such a hassle free way to save energy, I am not sure why these devices aren't everywhere.