IMHO, this is a marketing attempt to get the word out that Surface Pro/Book are competing for the same market as the Macbook <whatever>. They could spend a lot of money on advertizing and try to reach end users, or come up with a scheme like this where they might not actually fork out too much money and let news media do the job for them. At the sortof discounts they'll actually end up giving on average, its a win for them irrespective of how many people actually make use of the offer.

(Quite clever, methinks)