[PapaBear3625]

Probably did this the same way the old fill your gas tank with water and drop in this special pill scam worked. Secret gas tank hidden someplace in the car

This is why I'd like to see this unit run for a month, at a different location, under supervision.

For the case of cars with extraordinary mpg, the test also needs to be to run continuously for a month(using drivers in relays, or on a dynamometer) and see. Hybrid car makers are big culprits in this sort of scam, starting the test with full batteries and not counting their contribution.

[from occupied ga]

This is why I'd like to see this unit run for a month, at a different location, under supervision.

Which is why you'll never see that. There are so many ways to fake a demonstration that you could never account for them all.