For sure. If people want something enough, somebody's going to try to sell it to them whether or not it works. People really, really want lie detectors.

My experience in having a polygraph test applied to me after the business I worked at was robbed is that the results absolutely have no bearing on how the cops act afterward. They only bring you in for that in order to tell you that you failed, and should confess now in order to secure a lighter sentence.

Had I not had a family friend who was an ex-police officer, I would've been absolutely scared shitless during that experience. Even knowing they were going to do it, I was still absolutely terrified.

It's a fucking travesty that they are allowed to use pseudo-science mumbo-jumbo to terrify people into confessing. I lost all faith in the US police system in 2001 when I had to go through that. I have zero faith in their ability or even willingness to be 'the good guys.'

For who?

Mostly because of the placebo effect ie most people think lie detectors work and it makes you uncomfortable and stressed to have a device strapped to you while someone with authority asks serious questions.

It leads them down random directions because false positives are extremely common and more importanty false negatives can lead an investigation away from the truth.

It picks up one set of signals that can be altered based on the interviewer. And is colored by the person trying to understand the test.