[Mobhack]

Apart from the fact that vehicles in SP games have always had hull-down factored in, you mean?.

a) Dug in vehicles are hull down by default (hits are to turret, not hull)
b) Vehicles on higher ground are considered hull down to lower shooters (more %age of turret than hull hits, slightly smaller hit chance etc), the higher the height difference the more the hits are likely to be on the turret

(b) is perhaps unfortunate for the German Panzer 4s, as the hull is 8cm and the turret front only 5.. but good for the post-war Leo 1 of course!

There is no user-indicated "flag" that you are "hull down", but there is no need for it. Just get yourself up on hills if you want to be considered so.

Andy