Police jobs can be so difficult to get that, when an applicant has advanced to the stage at which they are required to take a polygraph, they are unlikely to want to make any sort of waves at all.

Also, in my case at least, I was under the impression that if I told the truth and did not withhold any information I would pass the polygraph without issue.  So I would likely not have been too interested in ending my chances of being hired by refusing to sign the hold-harmless agreement required by the polygraph operator.

If EVERYONE would refuse to sign that crapola piece of worthless paper, the polygraph would go away. Just a few won't work. It will take everyone. Who wants to work for an enity that requires hokey pokey to get hired anyway.

Does anyone here know of any successful, (or even unsuccessful) lawsuits against polygraph examiners for the tort of defamation, when they call an honest person a liar?

I have a law degree, but do not practice law, so I know the legal problems in defeating the standard hold harmless agreement that polygraph operators require the subject to sign.

Interesting insight here.  A couple of years ago, I agreed to take a polygraph test for a police position, and went through the whole pre-poly procedure, up to signing the agreement and release of liability.  I politely told the operator that I would not relieve him of liability in the event he falsely accused me of lying.  He then refused to admister the test!