exactly.
many accomlished or routine liars (the ones you really want to catch!) sail right thru lie detector tests
and
some honest people get so nervous being electroded and questioned .. that they flunk LD Tests even tho they are truthful
these reasons are why LD tests are inadmissible in court and why a normal person should NEVER submit to LD testing, imho.
too much risk of error that could cause serious problems
Ex agency. Have taken many polys. Do they work perfectly - heck no. Are they an important tool that should be used - heck yes.
And being nervous isn’t much of a factor - that’s taken to account in your baseline.