I wouldn't disagree with that. And a big problem is that innocent people tend to produce stress reactions when interrogated, leading to false positives. It would be appropriate to call a polygraph a "fear" detector, since that's basically what it's measuring. But still, the "science" isn't entirely bunk: some people do panic when they lie - though I read an anecdote that said this is a weirdly American trait (Europeans can cheat the polygraph more easily) - but it's virtually impossible to sift out the true positives from the noise.