Hi,
Let me tell you first about what I know of the meaning of the sentence below: The guests have to leave their rooms before or at excatly 10:00. Please correct me if I'm wrong.
Guests must vacate their rooms by 10:00
Many thanks.
Guests must vacate their rooms by 10:00
Ferdie:
This means that the guests can vacate the room before 10.00 if they want to, but they must not be in the room after 10.00.
not a teacher