Hi, being able to shoot from the vehicles is a great feature. But in my opinion the default "stance" after entering a vehicle should be normal sitting without the weapon in our hands +we also should be able to holster it away if put up previously. When full truck and not in combat, it would just look too bad - everybody aiming at each other instead of idle sitting with hands on their legs.
So in short: Putting the weapon out while in the vehicle should be a manual action only when needed, and we should be able to also put it away either manually or automatically as well after some timeout.