Peter: Seems a bit draconian, no? (But see, *, below). I was going to shows back in the 70's, when they were still CES at McCormick Place, and have been to my share over the years. How anyone thinks that any meaningful evaluation can be done, positive or negative, in the context of a trade show is beyond me. I applaud the dealers and manufacturers who attend these shows- no doubt a lot of tire-kicking, carping, and snark to go around in the corridors and rooms, even without the Internet- and, probably by people who in all likelihood have no intention of buying such gear in the first place. (If you were going to thown down 20k or 100k or more on some of this stuff, I would expect you'd want more than a listen at a show before you whipped out the old Centurion card, or whatever the card du jour is these days).
Obviously, the trade does these shows because they have to; and there are no doubt audiophiles who enjoy them for what they are.
As to comments about what was heard at a show, I think there always must be, explicit or implicit, the caveat that it was under "show conditions." I suspect most people here, who have been around the block a few times, know this- that even a negative report from the front lines is not the last word. [*I'm guessing your concern is folks who do take such negative reports as a valid review].
For more seasoned non-industry people, I would think going to these shows is just a way to get together among those with a shared interest in the hobby/gear/whatever. But, for those in the trade, I don't envy you these shows.