I guess the lie detector checks your heartbeat when ya say something. Ager app ghabraein hui hon, aur app boldein k unhon ne app k saath esa kiya aur ager Khuda Na Qaasta Lie detector ne show kiya k app jhoot bol rae hain tou phir masla hosakhta hai. Dont take such risk. Yea idea i guess sahi nahi. I m sure that i heard it notes your heartbeat and then shows the result, that whether you are lying or not, dimagh main kia chal raha hai yea tou padh nahi sakhta. So like KC and other said, you should arrange a handy cam and create a evidence.
I didn't think about that. It seemed very reliable when I read about it.