If not "detected", they can be "strongly suspected".  Either way you will get the boot.  You can argue that "strongly suspected" is nothing more than a wild ass guess, but that wild guess is always in favor of the polygrapher.  So if the polygrapher even thinks you are using CMs, you are done.  I think that I was "strongly suspected" because after my interrogation and being accused of altering my breathing, I was asked if I would be willing to come in for another polygraph, to which I said "yes".  Well, I was never invited back in for another poly, I was later rejected instead.  You can roll the dice if you want to...