If I remember correctly, I think the Kzinti and ToE talked about this at one point, and agreed to never use it. Maybe a Tyrant can tell me if I'm remembering accurately.
I think what you're referring to was an exploit where multiple buildings of the same type could be built using a bug related to the planet build queue. If I'm not mistaken this bug existed in DA v1.80g but was corrected in later DA versions (this screenshot was taken from DA v2.01). As I remember the Kzinti Empire and ToE did agree to not use this cheat/exploit and in fact I did *not* use this exploit.
Well, considering you cant get multiple Mind-Control Centers without using a cheat/exploit
Actually you can.
As far as I know the method used to achieve this was not known by the ToE (but was known to the Kzinti Empire) and requires getting multiple opponents to schedule the building and then conquering the planet on which it was being built. At that point you can delete the building from the conquered planet's build queue and then place it on the same planet where your own MCC is scheduled. The key is in getting all the MCC's from multiple opponent's planets all queued up on the same planet. Once a MCC is built all other MCC's on all *other* planets are deleted from their respective build queues. However multiple MCC's on the *same* planet are *not* deleted resulting in my case an 800% economic bonus.
This is the same method used by Maiden666 in his 1,551,200 point ZYW. This game was defined as not MV legal because of it's use of Dread Lord opponents *not* because he was able to get 3 or 4 MCC's on the same planet using this method.
In any case I doubt there's many left here that care one way or the other, but just to be clear this has nothing to do with the planet queue cheat/exploit that the Kzin and ToE agreed to not use.