[UncleOxidant]

tl;dr: polygraphs aren't reliable and can be misused?

[breve]

It's not that they're unreliable, they simply don't work in the first place.

The misuse is that they're used at all.

[Spooky23]

It’s a prop to conduct an adversarial interrogation without the same stigma.

[tokenless]

And they are performed interrogation style but cannot be refused without risking your career.

OTOH, someone arrested can (probably should?) refuse.