[minthd]

They have an error rate - which makes them in admissable as a tool for deciding whether someone should go to jail. That's reasonable.

On the other hand, their are routinely used in classified agencies for some tasks.

So maybe ,even with this error rate, we could see reduction at trafficking , at some risk of loss for freedom of profession. Maybe the benefits are big and the disadvantages are quite small(depending on error rates, etc) ? Maybe it's a worthwhile tradeoff ?

[roel_v]

You make it seem as if lie detectors somewhat work, except that they have a stochastic failure rate of x%. They don't, they're snake oil. Whole libraries have been written about it, one can start at https://en.wikipedia.org/wiki/Polygraph and follow the literature from there. No civilized country allows lie detectors to be used for any 'real' purposes except the US.

So no, it's not a worthwhile tradeoff, because it's hardly better than rolling dice.