I have to write it somewhere - because what is the point of a belief that does not allow you to make predictions that you are willing to stand by - and I guess this is the place. I believe that Hermione is not dead (duh!), and planned this all for the purposes of getting Harry out of his debt to Malfoy and/or preventing herself from being used as a weapon against Harry. She used or was discovered by Fred and George who were subsequently memory charmed by Dumbledore, who has spent entirely too much time off-camera of late.

Edit: I'll add that - on the odd chance I'm right, and this ends up sounding like bragging - I don't think that makes me particularly clever; I think it speaks to skillful but subtle hinting on the part of the author.