I guess I already know the answer to this but.....
According to Digital Spy
sky are going to start broadcasting 15 rated movies before the watershed on Sky Movies 1-9. They can do this because they will be pin protecting the broadcast so you will need to turn to the correct channel at the right time and then use your sky remote to enter in your pin number to see the movie.
My guess is that this means that if we select a film to record or TiVo auto-records and an early viewing slot is selcted we wont get to see any more than around 2 hrs of blue screens and an "Enter Pin" prompt.
Another emerging compatability issue.