A number of reasons mate, if this product is so great they wouldn't charge so little for it. The store says there are '148' items left, but the advert says they'll send you the 'product' by e-mail, if it's digitised, then there could be infinite copies of it. I'm also pretty sure that you'd need some kind of hardware to convert the signals from Sky to be read by your computer, but you can't e-mail hardware.
To put it bluntly, I just don't believe a word they say.