system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] Why doesn't Superman (or other Kryptonians) use the Daredevil lie detector technique more often?

Daredevil uses his super hearing as a tool to listen to one's heartbeat to see if someone is telling the truth or not.

It recently occurred to me, why doesn't Superman do that too? I know he can and he probably has at least once, but why doesn't he do it on the regular? 

I wonder if it's an ethical thing with him. Even Foggy (in the Netflix series) found Matt's use of it questionable. I think Clark might also find that "crossing a line."
gpt
He does. But he doesn't really question people. Even criminals he tries to encourage to do better because he wants to save them too. He always looks for the best in people.

It doesn't work on Batman, after he used it once Batman figured out a way to mask it (mostly so he could do the whole disappearing when Clark turns his back on him thing.) He still calls out Bruce though because he knows him well enough to know when he's not telling the whole story.

The super hearing thing isn't even Superman's best lie detector, he can see across the entire spectrum of light which let's him see slight temperature changes in your skin. His sense of smell is also just as good as his other senses, enabling him to detect minute changes in hormone levels as well.

You cannot directly lie to Superman. You may be able to fool him, but only because he is giving you the benefit of the doubt because he wants you to do better, wants you to BE better.