I too have heard the increased volume in a number of these non-believable tests. They spend so much time swapping things that one has to have good memory of what was there before and after. The trick, if indeed true, with using different recorded tracks at different volumes/processing would definitely explain why it is so hard to find out what they are doing. Then again, it takes extreme courage to engage in this sort of deception. The risks are immense.
I will be on the look out at the next show as in this one, I did not spend any time in their suite.