The inspector for a house I had did the post work inspection on a radon mitigation install. That’s how permits often work. You buy the permit from the local government, the work is done, and they send an inspector out to say whether or not the work has been done right.
The inspector didn’t know what radon was, stating he’d never seen anything like what we’d had installed before. The prior house owners didn’t know what radon was. My realtor stated most people think radon is made up. By whom and for what neither of us could figure out.
The inspector who doesn’t know what a radon system is had been doing mass approvals for new construction SFHs in that area. He approved the radon system in that house, stating: “I don’t know what it is but it sure looks like it’s been built well.”