The comparison with the TSA relates to its effectiveness against real threats. Sorry, that wasn't very clear. The polygraph isn't as good an analogy because it

The comparison with the TSA relates to its effectiveness against real threats. Sorry, that wasn't very clear. The polygraph isn't as good an analogy because it takes skill to beat. Gaining the skill takes time, so isn't as easily obtainable as materials that change someone's profile or features.