By hot seating, I think originally it literally meant different people jumping into the same PC chair to continue playing/doing something on the PC without pauses.
When I use it I mean players taking turns signing in to keep an account actively playing.
I am being looser with the term though because I would consider it hot seating even if it wasn’t 24/7 play, because obviously it would be a problem well before an account managed 24/7 play in GoW that we’d want to address before we had accounts getting to that crazy stage.
So we do have some players sharing logins (we super don’t advise this as it often ends up in account ownership disputes). But I haven’t really seen anyone playing competitively that way and I don’t often see it. I would definitely raise it as an important thing to address if it started affecting other players, and I know the team would agree with me because I remember having a conversation with the Producers about our stance on account sharing ages ago.
Side note: we do have solo players who will go through spurts of playing for a 24 hour period because gamer life 
We do have some quite hardcore people in game.