"There was - possibly still is - a crossover group typically made of electrical/electronic engineers who knew just enough traditional EM theory to be dangerous, but not enough to know what they didn't know about GR and QM."

The same can be said for physicists and mathematicians who know just enough EE. As a practicing EE who specializes in RF and antennas, I've had to debunk many crackpot antenna and circuits, who developers are looking for funding. The nice thing about RF is hunks of dielectric and conductor are pretty easy to fabricate or simulate, but they don't even try to prove their ideas.