Sponsorship - a dangerous thing...
I was at that gig. My mate fell out of one of those trees halfway through their set.
The Daleks tried this sort of thing in Power of the Daleks - basically there were only 4 Daleks but they made a 2D backdrop poster of themselves to make it look like there was loads of them - they also kept going round in circles to fool stupid humans into thinking there was, like, an army of daleks. Of course, our favourite Time Lord saw right through it.......http://www.youtube.com/watch?v=w2oN6GgAIdo&feature=related