15% degradation is not reasonable. I would suggest when a PoB is 1/3 decayed it would start to be considered as abandoned.
In the spirit of goodwill and to right wrongs, BretG should quietly request the Admin to return these bases. It would be fair as the BretG had no right to issue a decree to destroy decaying bases when there was no law regarding it. It would be fair and in the spirit of the game.