It's not just engineers. This is a risk for anyone who is proud of their specialty. Too many feel that it gives them a leg up on any technical issue. I deal with my share of arrogant electricians who seem to know everything about everything -- except how to make stable low voltage connections and how to avoid nicking the wires in network cables.

I had one experience that was laughable, but I managed to restrain my giggle. I had just finished repairing his receiver. There was a known issue with a power supply regulator and some bad PC board connections. It was a very straight forward repair and there was a manufacturer's bulletin. As he picked up the unit he asked a reasonable question: "What was done?" I explained and he challenged me with "I'm an electrical engineer and you should have replaced the IC" as he stormed out. There were no IC's on that power supply board. One symptom was the FM tuning meter was pinned off center. Yes, there was an IC involved (on another PC board) there, but it could not function if half of its power supply was missing.