I took one when I was a kid to get a job in as a stereo salesman. The idea that it could detect if I was not telling the truth kept me honest. The person giving the test (interrogator) is the biggest factor. A good one can get the truth out of you without the machine. It just helps them to "make" you tell the truth.

Now that I am older I realize that it was a big invasion of my privacy. I would not do it again.

I got the job.