Yes that's how it's used. That depends on people believing polygraphs work though, which is why polygraph companies for decades have been litigating against people who question polygraphs. Sometimes just the idea that there will be a polygraph test is enough to get people to be more truthful. It's like placebo drugs - if it works somehow, should we care about whether it actually works? By that reasoning, should we allow homeopathic drugs for healthcare insurance reimbursements? If Josie doesn't have a headache after taking pills, does it matter whether those pills are paracetamol or water with a story of it being very potent water? Fun discussions, not very productive, but still fun (for a while).