There was an ad doing the rounds recently in Europe showing a geek setting up voice-activated home automation. And then getting a tooth removed under heavy anaesthetic.

Turns out "Mmmmffmghfff!" is not a valid Alexa command.

Also a bad idea to have a voice activated door during torrential rain. (Which is a silly example. But even so.)

It's not even a UI problem. No one is going to be happy if the power goes off and they can't get in or out.

Or the lock fails open and everyone can get in and out.