So I sat for my exam at a certain LE agency and following the advice in TLBTLD, I bit my tongue after every question I identified as a "control" question.  Not too hard, just enough I thought.

After the exam, the examiner accused me of attempting "countermeasures".  I knew there was no way he could tell and I denied his accusation.

He then pointed to the headphones he made me wear during the exam and said there were "very sensitive" sensors in the headset that picked up my tongue bite.  I said "BS", and he told me to put the headset on, then showed me his screen and told me to bite my tongue.

Damn!  It picked up every one.  I still denied doing anything and walked out, but damn!  Really? What's up with that?