Generally, it is "frowned upon." This was our first real attempt at chairman's so most of my knowledge id really just advice from others.
At the district we attended, there was not even a way to show a video (we were in the counselor's office of a small school.) Luckily, we had a presentation prepared.
It does kind of sting, though (especially as one of our presenters). The only negative comment the judges gave was "improve public performance skills." Showing the video night have helped in this regard, and maybe offered us a chance at winning. It's hard to say.
This was our team's first real attempt at Chairman's, and with many of our seniors graduating, it's sad to think we probably won't be submitting again in the near future.
Hope this helped (before the Chairman's masters get a chance to share their experience
)!