that's true, but going even further to the opposite by forcing no spawns at all is also thereby even further bogus.
You could have a certain number of spawn exits, and have the entry point direct you to one of them at random, so that to effectively stop any arrival point for GVs, you'd need to destroy all of those random, marked or unmarked, points, sorts of neutral mini-VHs or simply rally points with minimal defense or structural strength. Sort of like the hotspots in Finrus.