Who can see a hotel (Hotel Console, Visibility): everyone on the tour (the default) or only specific people and groups (Managers, Band, or people you tick).
WHO IS LEFT OUT: anyone not picked never gets the hotel at all, on any screen (day page, calendar, day sheet, phone app). You and your tour managers always see every hotel.
JUST THE PEOPLE STAYING: when the hotel has a rooming list, one tap picks the people on it, for example only the bus driver on a day the band sleeps on the bus. Names on the rooming list that don't match anyone on ATOM (no login, a nickname, two people with the same name) are listed so you can tick them yourself; ATOM never guesses.
ON THE OVERVIEW: a limited hotel keeps its place, and its cube reads Just for: with those names, so you know at a glance it isn't everyone's hotel.
WHO CAN SET IT: tour managers and admins. Travel agent accounts can't change who sees a hotel; ask your TM.