Okay but how about using this in conjunction with polygraph for some high stakes case where you'd benefit even if you can have slight confirmation of truth. then interrogator (for lack of better word) can structure questions such that you lean the conversation towards truth.

In fact now that I think about it, even 'pleading the 5th' can be worked around using this type of setup.

True, but yet they're still used with certain job applications, with criminal investigations (the results just aren't used directly as evidence), etc.

Most people believe that polygraphs have some amount of validity, and that's a problem that means they continue to get used and continue to do harm.

> Most people believe that polygraphs have some amount of validity

They have a much higher rate of false positive than false negative. That makes them useful in circumstances where your primary concern is, say, eliminating risky hires for jobs accessing sensitive data -- you may lose lots of good candidates, but your concern isn't fairness.