It's a ticketing issue........
If a passenger books to fly with BA to LHR with a connection with VS onwards (as per the current agreement) then revenue and booking info flows to BA - a competitor. The pax is also delivered to the "wolfs lair" in T5 and needs to transfer to T3.
With Little Red Riding Hood to the rescue, the regional passenger can be securely transfered without falling into the clutches of the "big bad wolf"
