Great response from Nest. But honestly - their algorithmic "trust us, the device knows what its doing" approach has always made me uncomfortable. The thermostat for instance - I don't want my thermostat to learn my habits and predict what temperature I want, etc. I just want to tell it what temperature the house should be and when, and leave it the hell alone.

Same thing with the smoke detector. False positive? Push the button. Its the rational ux given the criticality of failure modes involved.