Still waiting for the more highly motivated and skilled among us to come up
with a detector that would mount in the engine compartment, or on underside
of the rear deck lid, that would monitor for flames, or an unusual increase
in  heat output.

Obviously, the fuel needs to be cut off, and the occupants notified  as soon
as possible. By the time one sees the flames through the deck, or out the
bottom, its probably too late.

I know it could be done. Exactly how, is up for debate :-)

John