The trick itself is nice.
However the trailer does a good job of looking like a full
performance. However cutting out a section of the performance, which, given the angles they film at
in the trailer, makes this effect look much more than it is.
I bought this because the
trailer appeared to disprove how I thought this was done, how wrong was I. I can't say any more on
this for exposure reasons, but if you think you know how it's done, you probably do.
I can
think of more than a few audience management issues as well