The suggestion is as follows:
Having ONE Grand Master Crafting Station placed in a house, anywhere, causes ALL crafting stations of that type to behave like Grand Master stations, with access to all the "known" attuned sets that you've unlocked so far. "Attuning" your crafted sets would have to be tied to the account, not to the specific GM crafting station (if there's anybody out there with more than one GM crafting station of the same type).
This would allow for creativity in player housing, and in particular, in player housing that is meant to be accessible to other players than just the house owner. (For instance: Guild houses.)
For instance... So long as you *owned* a Grand Master Blacksmithing Station placed somewhere in any one of your houses (to attune sets to), you could actually use something else, like an Anvil of Old Orsinium, as your *effective* Grand Master Blacksmithing Station in a different house. Or you could use a Clockwork Blacksmithing Station if you decided to buy one of those with crowns for the look of the thing. Or you could even use a plain old regular Blacksmithing Station if you want to look cheap.
It wouldn't change the effective ability but it would be infinitely cooler.
I'm imagining a guild house which uses an all-Antiquity set as their Grand Master stations...