A 'lie detector' once cost me a chance to get a job.
On the day of the interview I was sick with disentary and needless to say a bit squirmy.
I asked if the test could be put off to another day but no... it was now or never.... "Well" I thought "I have nothing to worry about, nothing to hide".
At the end of the test I failed miserably "Lying" about 80% of the time

Of course I wasent lying but squirming about trying not to soil my breeches.
Looking back on it its probably a good thing I failed as it forced me to look for other work which ended me up in the carrier I am in now. No lie detectors needed.