Police departments don’t use polygraphs because they don’t know that polygraphs are voodoo crap pseudoscience. They know that. They use polygraphs because they think suspects don’t know it. They think a guilty suspect is more likely to refuse a polygraph. Refusal is possible everywhere, the courts know its junk science and so don’t approve warrants for them. The results are not admissible as evidence in court because it’s not reliable evidence. Polygraphs help the police get confessions from criminals who don’t know these things. Polygraphs are dangerous for innocent suspects or persons of interest because you can fail it even though you’re telling the truth. While that can’t be used as evidence against you it will insure that the cops will continue to investigate you while ignoring other evidence that might lead them to the guilty person.
The solution is that polygraphs should be prohibited not only in law enforcement but in government hiring as well. A good detective has a built in lie detector that’s probably a lot better than any polygraph machine. If I were the boss of a police department I would not allow polygraph machines in the building because I would not want my officers distracted from doing real police work and catching bad guys. For the same reason I wouldn’t let them run speed traps.
The Federal government is not happy with Doug Williams for teaching people how to beat the test. They’re trying to bring a criminal prosecution against him. I think they’re going to have a problem with the 1st Amendment. Not to mention the junk science problem. Do they want more people to know about this?