This may be a bit of a tangent but some years ago I sat through the early hours with a group of people in an ops room in Manchester worrying about a plane load of delayed passengers. On the ramp was someone else's B747 not going anywhere until the following afternoon and in a hotel we had a full crew capable and qualified to fly the beast if it was in our fleet. The aircraft's crew were overnighting in a local hotel and the airline had no based staff at Manchester.
The conversation revolved around who would know if we pretended (lied) to the airport duty people that we had leased the aircraft, boarded the passengers and flew to Malaga and back and left the aircraft on the ramp back where it had originally been parked.
It would fly under our flight numbers as a delayed flight so ATC records would tally.
The only record anyone could think of would be the clocks on the engines.
What did we miss?