If you dress well for an interview it is commended; if you shower for an interview, it is necessary.  If you calm yourself for an interrogation (ie polygraph) it's not, you're a cad??? If the thing is soooo accurate, there should be no concern re countermeasures, or any other tactic that be employed.  Otherwise we should just roll out of bed without combing our hair or brushing our teeth to show up for an interview.  Polygraphs are unfair.  Period.