I wonder if it is in response to Osana Reimu or just their own headcannon.
The deal about her ribbon (actually an ofuda) has been there since her creation considering that she is unable to touch nor remove it. Which indicate that something or some aspect of her has been sealed.
So it is more how she was before getting "ribbon" that is fanon and the ofuda being a seal being canon (at least the part about her being unable to remove it).
