Most videos of model railway shows are shot by enthusiasts. Because of this, they tend to be heavy on the trains and don't really capture the essence of the event.
This promo film by Warner's video people (the same ones who make the BRM DVD) is interesting precisely because it hasn't been shot by enthusiasts. Instead it shows people enjoying themselves and to my mind, catches the feel of visiting a show if you aren't a hard core model railway nerd.
It makes visiting a show look just as much fun as it really is. And yes, I can be seen in the background towards the end, but watch it anyway.