Ha ha ha...........
Polygraph test is the technology that is meant to be used to prove the guilt and not to prove the innocence!!! This is the first principle of the theory of investigation and evolving science in it!!
Even DNA and finger prints are meant to narrow down on culprit and ........ it is not an adversarial thing AS AN "AID OF TECHNOLOGY" FOR rescue of SUSPECTs!!
It's the prosecution who does all efforts to prove a person guilty if found enough evidence.
A innocent person who's charged with certain punishable offence has to do nothing!! ............ Unless prosecution tries to fabricate the false evidence to frame a innocent party AND in such a case the innocent party may demand that those witnesses giving evidence against the suspect be polygraphed.
The suspect himself can not demand onself to undergo polygraph test!!! (The person is already a suspect and there is a huge chance that he may resist the technology which hasn't been yet mature and fullproof!!!)
Polygraph test is effective on kids and 'young minds'!!!
If you have guts and courage and really convinced that you are innocent ....demand the water boarding test!! and give an undertaking that ................. you prefer to die in honor! ............ but in the fear of death you won't concede to admit any offence which you never committed!!! You will be aquitted in one day after the test!
I am just joking.....................Above para you should take it in a playful manner!.....please.