I agree that such an important rulechange shouldn't be as easy to accidentally overlook. A post in the announcement section is the minimum I'd expect for something that will get whole factions sanctioned after a month.
Furthermore, like Blodwyn, I fail to see the point of this rule given that a lot of official faction IDs are literal copy-pastes of the NPC ID. It is much preferred that you could choose for yourselves if you want to use your ID or not. If the ID makes any difference, it should be up to you if you want the benefits or not.
As it stands, this has potential for just being sanction bait for no reason whatsoever.
