There also other things, like pillow talk etc.
And I simply don't want anyone else to take part in that, whether they are russian, chinese or NSA hackers, or the company by itself.
And I usually tell people in their face, what I think of them.
Perfect example. Do you always ensure there are no smartphones within earshot?
But I would certainly try to do this in this situation as well.
It is not only privacy btw. it is also just nice to have both persons here in the now and not half distracted because the Smartphone just got new messages. Could be important... but usually never is important enough, to destroy the moment.
So when I go to sleep, alone or not, the mobile is off (without battery) or away. Unless there might be a emergency and I need to be avaiable, but those situations are rare.
Is there nothing you've ever said about anybody while in the vicinity of a smartphone that you wouldn't have said to their face?