Re: The responsibility of an expert . . .
I agree with all your points Sam. However, I think you might be expecting too much from some people when it comes to qualifying statements.
I can only speak for myself here and say that part of my "upbringing" as a professional skeptic has been to be skeptical of statements, including my own.... I believe this teaches one to be careful and qualify their opionions. My guess is that this is has also been part of your professional experience. Unfortunately, many people do not share these sentiments and are either not aware of the impact their statement might have or perhaps they are trying to create an impression of an all knowing expert.
I think the way to deal with this is by requesting a reference or the reasoning behind such a statement/conclusion. If this is not provided then any such claim should be taken with a grain of salt..
Just as an example - I was recently involved in a thread regarding the question of whether the US customs can confiscate a Rolex watch that was mailed from outside the country. I responded to the OP that as far as I know- this is true and stems from the fact that Rolex has recorded their trademark with the US customs and that importation by mail, even by an individual, is thus a trademark violation. In response to my post - another poster, who eluded to the fact that he is a customs agent, claimed I was wrong and that the ban only held true for the importation of NEW items, but not for USED items. In response I asked the poster to provide a reference for the OLD vs. NEW claim - as, to my non expert eyes, the fact that the item is used should not have a bearing on a trademark violation..... A week later I am still waiting for a response from the "expert".... So, in this case, my opinion remains the same...
