For a less-volatile example, my anecdotal/observational experience is that mathematics cranks (the angle trisectors, circle squarers, anti-Cantors, and so on) a

For a less-volatile example, my anecdotal/observational experience is that mathematics cranks (the angle trisectors, circle squarers, anti-Cantors, and so on) are disproportionally engineers, and in particular electrical engineers.