Right but here's the text I'm looking at:
"A character riding a chariot or a monster cannot move
into terrain that his mount could not enter. He cannot
enter a wood for example. He cannot join a unit if all
of its stands are in a wood."
(Main book page 63)
Doesn't this mean that while the Djinn is a "ground mount" officially, the wizard mounted on it cannot enter woods? Not because it's a flyer (that is discussed on page 66), but because of the "monstrous" property.
The same rule is in the living rulebook (same page).
Believe me, I would love it if Araby gets this this-- it's a cool property and I don't see much room for abuse. But I'm not sure the rules as written support the conclusion we've all been reaching about it.