J.K. Rowling uses an interesting foreshadowing technique for her final Harry Potter book. Here is an excerpt from the first chapter.
Harry Potterawoke to the sound of birds gleefully chirping in the wild of their makeshift campsite. Hermioneand Ron had already yanked themselves from slumber and were daintily cooking the chosen one's breakfast. The three heroes needed their energy if they were to destroy Harry's immortal enemy who gets discussed a lot, but never really does anything and will never really die until the money dries up. Harry, Ron, and Hermionemust band together as vicious vigilantes and harness Professor Dumbledore's dying gift, a purple AK-47 that fires magic bullets and wizard lightning if they want to destroy yet another outlandish reincarnation of Voldemortonce and for all."
I honestly think the use of a strikethrough so early on gives away which characters are going to die in the end. Plus it would be really annoying to read it like that for the estimated 1.25 billion pages of book #7 (hard cover). Hopefully Rowling will revise a lot before the official release, because I also don't like her idea of the final battle being between Harry and the final Horcrux of Voldemort found in Aunt Petunia's brassiere.