ABC did something similar by making the first scene of FlashForward available online before the premiere. Now ABC has done it with V, as well. Having seen the pilot (which I liked) for my viewing pleasure, this was the best part of the pilot, and I will watch it again when it premieres on November 3 at 8pm because it was meant for the big screen.
V has had some noted issues, with production being put on hiatus for a while to address those issues. Then ABC announced it would air the first for episodes but then put the show itself on hiatus before bringing it back sometime in the new year.
Here's the video preview of the opening scene: