Everyone has their own computer in our household, and then we have a “walk-up” for anyone to use, including guests.
I can tell you from watching evening and overnight guests that anyone under 30 views a computer in plain sight as an available resource and will use it without asking. Anyone over 35 or so will ask if it is okay before they touch it.
And I can’t be the only one who, as a teen, did it with babysitters (they invited me over) in the LR after the tikes were asleep. Very exciting, not knowing if we’d get caught by the parents! Fess up, fellow piggs.