Devil's advocate (sort of):

Some will say that the fear of a random 'full meal deal' search will cause a bad guy to get tense and start displaying signs that a BDO or spotnik will pick up on.

Others will counter that 1) our own special forces folks are trained to avoid 'tells' in stressful situations and 2) TSA has no intention of trying to ramp up BDO surveillance enough to make it likely that the hypothetical bad guy exposed by this stress will get seen and caught.

I haven't seen any actual reliable studies to demonstrate that this is more than speculation (or wishful marketing on the part of people who stand to make $$ off unproven 'science').