Actually, that's one of the reasons I'm in favor of this suggestion. I find it really confusing when suddenly the icon changed, and it wasn't until I noticed that the favicon had also changed in my browser tab that I understood that those new usernames were pointing to the ao3.

Also, isn't hotlinking generally considered bad form? Even if it's just the favicon? I always felt that way, but maybe I'm just so five years ago in this belief.