There seems to be a few factors that are contributing to the consternation revolving around this social experiment, but mostly it is about a lack of reference and a lack of a standardized, controlled experimental method for trying to detect and measure a phenomenon. With all of that ambiguity, what are we discussing other than a flawed process?
If anything, this points out the wide variation in people's interpretation of a supposed constant, known stimulus. Add to that the idea that the stimulus may not actually be remaining constant across viewers, as well as the bias and unreliably variable descriptions of the viewer's interpretation of the stimulus and it is no wonder the whole "discussion" is a confusing morass of disagreement. There is no control over the process or the variables requiring control to measure the signal.
Hey, at least it gave me the opportunity to bore the crap out of my kids by explaining and demonstrating to them the difference between incident and reflectance metering, and why black cats and snow are gray, unless you do something about it.
kirk