You have brought up a good point.The different preferences might have been conscious bias (or an agenda). I don't know. Bias (and its evil twin politics) wasn't something I had considered from the people who where not exhibiting.
It makes sense that a speaker builder/seller would be biased. How could they not be? If they go to the trouble of building a speaker it only follows they will build one that is pleasing to their own taste. For example, Wayne often excuses himself from making observations about other folks gear because he knows he'd appear biased. It is a given that a vendor would be biased towards their own creation. No news there.
But you are right, there could be a great deal of bias for the folks who just came to listen.
Admittedly, the premise of the audio show in small hotel rooms may be seriously flawed but it still is a way to get exposed to a lot of different equipment.