No, I’ve never been in a situation where it was required.
Lie detectors aren’t 100% accurate; which is why their results are not accepted as evidence in court.
@Mariah
Their accuracy is dependent upon the physical responses of the central nervous system which are not under our direct control. Thus, it stands to reason that a person who is merely more anxious than normal about the entire procedure can come up as either deceptive or inconclusive so your sister’s situation is certainly not unheard of.
The other situation that could skew the results is if a person is sick or in pain so a skilled experienced investigator will inquire about that prior to the test and postpone it for a better time.
I’ve also read or heard (can’t remember where) that if someone is trying to beat the lie detector, they’ll do something to cause themselves anough physical pain (like putting a sharp pebble in their shoe to step on or biting the inside of their lip) to throw things off.
I don’t know how accurate that is but I’m glad I’ve never had to try it.
And I’ve also read that a sociopath can beat the test because they have so little of a conscience, compared to the average person, since lying is the norm for them and doesn’t cause any nervousness or apprehension for the test to pick up.
I don’t know how accurate that is but it makes sense to me.