Ah yes because people are always 1100% saying exactly what they mean instead of using jokes, hyperbole and other stuff. Just in case a pedant walks by and goes "hurr durr not a lie detector" when it's perfectly understandable to both people talking what they mean.
Wonder Woman's lasso does significantly better than our real world equivalent of at best, measuring somebody's stress when you've intentionally put them in a stressful situation.