Appearance of competence isn't even trustworthy.
I was shooting a volleyball team on contract with the parents for posters. As the teams were warming up a guy with a Nikon D3 and 70-200 walked in and set up some lights on the opposite bleachers. Then he crossed the court and metered the light. He was shooting on spec and had gotten the tournament to announce his website on the PA.
I knew my ambient shots were good and I was happy with them for the posters but I was curious to check out this other guy's work. I was shocked later to see that his remote lights were direct, and they created a look where the athelete's faces were nearly blown out while the background was almost black. He had all kinds of crazy shadows from the net and many of the shots were also loosely composed and frequently didn't include faces etc. etc.
I guess the lesson is that you cannot assume anything from the gear a person has or how knowledgable they appear until you see their output.

