I don't think that would work because you don't necessarily have to be inside the enemy's base in order to effectively spawn camp them, and actually entering the base itself isn't usually a good idea, because if one mech goes critical, everyone is boned. I've spawncamped the Clan base on Clearcut before by walking Vultures or Novacats up to the mountain north of their base 900 meters away. From that vantage point I can fire directly into the base, and I can also fire into the #5 hangar bay, which is the most commonly used bay to repair in.
In my opinion, spawn camping can be easily prevented by players doing one of three simple things: 1), players on the winning show a tiny bit of sportsmanship and back off or 2), players on the losing team spawn somewhere else or 3), take a different exit if there's only 1 base. None of the crazy turret nonsense previously mentioned in this thread is necessary, and I don't think anything like it exists in CBT.