Scott-S6 wrote: The open-topped rules just say that you don't have specific fire-points and everyone can fire. Nothing says you can ignore the other restrictions.
This: open-topped tells us in
it's rules that the whole vehicle is the Fire point.
Just the same as it tells us the whole vehicle is an access point(exact same wording).
If you decide that an open topped vehicle doesn't have fire-points and therefore doesn't have to follow their rules, then it also doesn't have access points therefore the only way to get a unit inside is to deploy them there, and the only way to get that unit out is upon destruction of the vehicle(via emergency disembark for Destroyed:Wrecked results; of unit placement for explodes).