It may help to be an expert in order to provide useful data, but a persons level of knowledge should never limit the information they can obtain. If that were the case, only the most brilliant children would ever goto school which greatly limits the pool of knowledge and possibilities.
Unfortunately, with claims as large as Global Warming the scientists involved will be inundated with both insightful and asinine questions, the latter far more often than the former. This is just the way it is and as scientists we should be prepared for this. Not by limiting access to the knowledge/data, but by presenting it openly and willingly, and defending it or revising it as needed. Obviously one can expect the occasional individual who can not be dissuaded no matter the amount of information presented, but they would be there with our without the data.
On a personal note, and as a conclusion, I believe that there is only one case where a person should be ignored and our denied access to information. This is when the individual, not a group, ignores everything in front of them and goes after the person, not the data. This is, of course, a very personal and highly subjective case which I don't expect people to associate with or even understand.