Well, let's see...

Look at people's behavior. Each behavior is an indicator of intent. Know which behaviors mean "deception", and you can spot deception. Isn't that the theory?

So, if you know which behaviors indicate "deception", why is it that you completely - perhaps willfully - ignore such behaviors in airport vendors and TSA employees, and only make LEO referrals on travelers?

Could it be perhaps that the entire concept is a giant steaming fragrant pile of horse manure? That the behaviors which BDOs are taught mean "deception" actually DO NOT mean "deception" and what they're really doing is calling the cops on random people based on their own personal prejudices and preconceptions?

Refresh my memory again - according to the GAO report, how much better than random chance is the BDO program? I'm thinking it was 0.0%, but I could be wrong. It might be 0.00%, or even 0.000%. Triple digits would be an impressive success rate.