This confidence she's exuding lately ain't for nothing. The more confident you feel, the more confident people believe you are, the higher the chance they'll take to buy your music. Exhibit A = Beyonce.
Honestly when you put all the pieces together with the whole blackout/silence for months.... it makes sense that she was planning something as big as a surprise release.
But she does have Roseland just a week later. She could tie that in somehow.