Quote:
Originally Posted by wordsmythe  The operator reads the machine and gives an opinion based on what they see. If the machine doesn't show indications that would change the operator's opinion then you've fooled the machine AND the operator. |
It's not that people are fooling the machine, more like the machines & measurements are not reliable.
Because of the unreliabilty, the courts & the scientific community, are hesitant to acknowledge it.
Why?
Because the tests could indicate innocent people as showing deception.
It's not an exact science like prints or DNA.
When you have time read United States v. Sheffer..