Well, if brazil84 is a lawyer, then similarly, by virtue of his expertise, it seems reasonable to me that he should not easily let his opinion be influenced by that of laymen.

That might make sense if the question under discussion were a legal question (e.g. how a statute is likely to be interpreted by a court). But that isn't the case here. In fact, even if the domain that brazil84 is claiming expertise in -- determining whether people are telling the truth or not -- were one in which lawyers were more likely to have expertise (and frankly I know of no reason to believe this), the fact is that it has precious little relevance to this case. This case is not about which human statements to believe. Instead, it's about applying Occam's Razor to physical evidence.