It would be of assistance to support what we already know. All five are lying and the Psychological Stress Evaluator would show it. Joran might beat it, the little psychopath.NSNR
"I have also been told that, as clearly hinted at in a previous post here, the boys have been given lie detector tests and said to have passed all questions except for the critical question of when they either were with, or saw Natalee last. This is now the second source who has conveyed information regarding a lie detector being used in the investigation."
This was on the Riehl World Website. It is on the first page and seems to be written by the owner of the site. He states that it is not confirmed but it seems to be stronger than pure speculation. I didn't see it posted here and am not sure whether Riehl World is considered reliable in any way.