First off, it should have either a long lockout after using it or it should be tied to the mogstation. Other than that, it doesn't hurt anyone to implement it. If the game has a jump option, it should have a go-back-to-level 1 potion, either in the job you want or all of them. You'd lose your armory bonus if you do it with all of them though. The system would flag the quests as "incomplete", remove the cs entry in the The Unending Journey and items in the Calamity Salvager. I don't know how hard is to code it to make it so the items you got from these quests get removed. It should also read the retainer's inventory to remove them.