When you are on board a car and have robots deliver an ammo type that can fit in the car's ammo bar it will fill the car first and fill player slots afterwards..
didn't test it on a tank but it should happen on tanks too...
BTW this seams like a feature to me ...
From The Eagle's Nest i can see to the ends of the world...
and from this vantage point I declare with utter certainty that this Game is in the Best!