As a night owl,I've noticed people who get up in the morning have life worked out way better than me.
If the ceo text people at 3am, excluded anyone awake to respond, and upmarked anyone who responded before 8, it would be a good cultural fit test for some places!
(I can think of one place that I wish had detected me as ' not likely to attend unofficially mandatory 8am scrums and saved some stress)
I rarely respond to any message on my phone outside "normal" hours .. with a couple exceptions (one being my wife)
And messages from unknown numbers? They get filed to possibly never be responded to (possibly blocked)