Breakthrough Vehicles Stolen in Spawn

After a sector is won, why are vehicles spawning before all the defenders are either dead or have retreated out of the area?  On Eastwood (transport chopper in Sector 2) and Blackwell Fields (Traverser in Sector 2,) I've had multiple occasions of players sitting right at the vehicle spawns and taking them as soon as they appear.  They are appearing while the defenders are retreating... Stealing vehicles is part of the game, but you should be in the combat zone and not in the spawn at the start of the new sector.  If the vehicles are there to balance out the game, they shouldnt spawn until the defenders have vacated the area.  If you get out of it and the defender steals it in the middle of the combat area, you were stupid, but if they're taking it before the attackers can even sprint to that location on the map, it's a poor design.  Please fix this