I know it can happen. Your sining a legal government documents when you check the box for at or below fair market value. So you better be able to back it up when they call your bluff!
but then again, a sales recipt private party to private part saying “I am selling my RX7 VIN XXXXXXXXXXX for $1000 as is (blow up motor) to so and so” I would assume would cover that bluff if they asked why it was so cheap