It's what makes the most sense in terms of the Ghost, I think. Enough time has passed for people to have revealed roles to one another, so if the Ghost possesses someone now then they have plenty of opportunity to maybe have found it out on their own. But after just one week? Not likely.

[ unless you like, really want to die or something. ]

If there is a role that can see other people's roles... flaunting that knowledge is awfully brave.