Although it would make more sense to have the A/C flying and earning money, you will probably find that they do sit there all day!
Many airlines do this for a number of reason, Slot Times, Airport Restrictions, Crew Hours etc etc. While in JFK a few years back waiting for my VS flight home i noticed many A/C that had been towed to remote stands once they had arrived, including another VS aircraft which arrived at lunchtime and left about 10pm. The inbound flight operating my return flight was delayed and we did'nt leave until 2am, i wish they could have just given us the A/C that was parked all day!!
I think VS park an aircraft in Jo'burg all day aswell, or at least they used to.
Regards.
