I ask this question to Warlord Games. Here is the Q&A
Q. Can Forward Observers call in Arty/Air strikes while in an open toped vehicle? (The question is HQ abilities vs not giving Fire order to passengers). I believe they can still spot for other on board artillery/mortars while in open top vehicles.
Can artillery/mortars Spotters spot from open top vehicles?
A. “An Observer can indeed use it’s Line of Sight to spot for indirect fire weapons from within Open-Topped Armoured or Soft-Skinned transports, but it cannot use their Fire order to call in the appropriate strike. As an aside, this means that Medics within a transport can use their Medic rule as with any Officer. Furthermore a Spotter cannot use their line of sight from the back of a transport, as they are not considered a HQ unit and therefore cannot benefit from this rule.
I hope that this helps!
Kind Regards,”
