Come come dont be silly... you might have sweaty palms because thats how you are, or you might be worried about your kid whos been in an accident youre flying out to see, or about a big business meeting coming up... good grief it could be nigh anything.
There's a lot more to the described devices and methods than just detecting sweaty palms. And even then, if you're not found to be carrying anything dangerous after an intense screening or you can pass a quick background check you can board the plane.