If I am not mistaken it is in direct response to multiple hawks being lost before ever being able to defend themselves or ever be in the fight.
RPGs on this server are highly buffed and easily acquirable by civilians, all it takes is one RPG for a hawk to be a complete loss or even one titan hit for the hawk to be completely useless because the pilot can no longer maintain control of the aircraft.
There's been multiple explosive devices introduced to civilians after this rule was implemented all this post is doing is attempting to remove gray areas.