Because there was Molly Weasley - while Hermione had hid Draco Malfoy in a room just a measly fifty yards away.  Because there was George, and Percy, and Charlie, and Hermione was hiding Draco Malfoy inside. Because there was Harry Potter, standing ever so elegantly at the alter, awaiting the love of his life’s arrival, and Hermione was about to unveil the attendance of Draco fucking Malfoy.