If I remember correctly, all you need to do is turn on the external GPU on aircraft like the 727 to be able to refuel it with no other people around and is parked with all doors closed and shut down. Therefore, the aircraft can have fuelling complete when the crew arrives.
Otherwise, a typical situation would be that it is just done while the crew is on board and we may happen to notice the fuel quantity increasing and when we see our desired fuel quantity, the seat belt sign is turned on for pax and wait for the fuel sheet as we do other preflight checks.
In other words, there is no policy when there are no pax on board in my experience.
Last edited by JammedStab; 9th December 2013 at 17:02.