I can see your point, but I think it'd be the equivalent of blocking or mining a vehicle store. People won't be happy if the vehicle they stored gets immediately destroyed or made obsolete by a few walls or an AT mine. I have no problem with people taking shots at the gunstore with their stored vehicles, it's only when they store the vehicle as soon as you return fire. Your solutions would only serve to make the gunstore harder to take and give reason for people to complain, where as a timer/cooldown would solve the problem of storing vehicles after taking fire, and would minimise complaints from either side.
No disrespect. Just Opinion.
MakingBacon AKA Sluggah