I'm not a polygrapher.  This is a true story.  Trust me, the polygraph machine from Layfette Instruments that is used is VERY sensitive.  Those tubes can tell when  you don't breath even for a split second.  And the fact that the polygraher is staring at you, don't even think about tongue biting or nothing stupid.  There is a sensor on the seat, so don't try the anal contraction.  I was busted.  I thought they were just accusing me of CMs as standard procedure but in the end I was rejected and got a statement saying that was why.  They knew.  I denied it.  But they knew.