No, to all of this. Purveyors of IQ tests for hiring brag about their client lists. It is simply not true that there is a prohibition on IQ testing candidates. There isn't a de jure ban, and there isn't a de facto one. The majority of companies that don't use them made that decision because the tests are stupid, not because they're a form of HR samizdat.

I already addressed the IQ thing, so to be frank I don't care anymore. I have nothing new to add.

I only responded because I don't like the implication in your last response that age discminiation is legal and companies are not in fact routinely sued over incompotent postings. In the company's fairness, they don't have perfect oversight of every manager and every posting. But they pay the price.

That is a pretty black and white area, and I mentioned the few grays already. It still happens. If you were just talking past me to double down on the IQ thing, then my apologies.

I don't understand and think we may be talking past each other. Age discrimination is not legal, and you would likely get in trouble at most big companies for asking candidates their age. Whereas, if you instituted an IQ test for candidates, you would probably brag about it publicly, as companies manifestly do.