Only thing I could think to do is spawn every vehicle and delete-all-of-these on each of them to see if the warthogs became something else
otherwise yeah I guess you have to move the map itself.
it can probably happen like how certain skybox elements in Halo 3 Forge counted against your Forge budget and object limit (ie The Pit) and you couldn't highlight those objects with the monitor even if you got out there, iirc. They stopped that practice with Reach but I imagine the code that was there for that still lurks
otherwise yeah I guess you have to move the map itself.
it can probably happen like how certain skybox elements in Halo 3 Forge counted against your Forge budget and object limit (ie The Pit) and you couldn't highlight those objects with the monitor even if you got out there, iirc. They stopped that practice with Reach but I imagine the code that was there for that still lurks