Conspiracy theory alert
There is always the possibility that KAL007, was deliberately sent to excite the USSR's radar and check what happened when a civilian airliner 'accidentally' intruded into USSR airspace near Sakhalin Island. The whole thing was eavesdropped by US AWACS, right up to the firing of the missile which killed all on board.
Another Korean Airlines plane was shot at by Soviet Migs when allegedly 'flying over the North Pole navigating by magnetic compass' it ended up over Murmansk. The pilot only landed after the cabin was pierced by several bullets from the Migs killing a couple of the passengers.
It will not surprise you to know that I have never flown Korean Airlines.