I think the point was that you can use emergency disembark to exit the vehicle as if it were open-topped, and gain extra distance that way. Emergency disembark (henceforth "ED") isn't always 3" (it's shown in the diagram as 6"), but in the case of a Wrecked vehicle it would be 3". ED'ing in the opponent's turn (i.e. after a Wreck) would also avoid the drawback of ED (except for Overwatch).
Anyway, back to the
OP: I would say that the two are examples, rather than a complete list (though it lacks an "etc." or anything to make that clear). Listing all the possible reasons you aren't able to place a model would get prohibitively complicated quickly, with no future-proofing. That's
HIWPI rather than strict
RAW though.