"Secondary screening" is often misused in this forum. There are three types of screening:
1.
Selectee screening. This refers to the computer-generated mandatory screening signified by the
SSSS on the boarding pass. Federal regulations promulgated by TSA spell out the criteria for selectee screening, and the airlines have the authority to make certain exemptions. As posted previously, I personally don't think selectee screening adds to security. However, I recognize the political reality that this type of screening will never go away. It's a lot like seat belt laws in that no one will step forward to lift the mandatory requirement without suffering major political repercussions.
2.
Continuous screening. This is the practice of screening passengers at random even though they successfully passed through the WTMD. The concept here is to pick the very next person (in order to avoid allegations of racial, ethnic or other forms of discriminatory profiling) for repetitive screening as a back-up to the primary screening. I object to this practice for two reasons: either we did it right the first time or we did not; therefore, no need to do it again....and, after a person who goes through the trouble to correctly divest all metallic objects, perhaps even remove criteria shoes and successsfully pass through the WTMD only to be picked for random screening strikes me as pure harassment. I think that once a person successfully passes through the primary screening method (WTMD), then that person should be cleared. However, I don't share the same approach when it comes to continuous screening of property, and I think random screening of carry-ons, particularly electronics and especially laptops, is a prudent measure. I mention laptops because the majority of the time, they are already out of the bag, and it is no more inconvenient for the passenger to place it back in the carrying case after ETD screening than it is after x-ray screening. Still, nowadays, I simply don't have the luxury of continuous screening. Our manning is at a bare bones minimum, and I prefer to send screeners to breaks whenever there's a lull in the traffic flow. They come back to the floor refreshed and with a more positive attitude.
3.
Secondary screening. While used interchangably with the terms above, this term refers to follow-up screening to resolve alarms or concerns from the primary screening methodology. In the case of the passenger, when that person alarms the WTMD for the second time, hand-wanding is the secondary screening method to resolve the alarm resulting from the primary screening method. It also applies to physical/ETD checks of property that either contain prohibited items or appear to contain prohibited items on the x-ray scan, or are so cluttered that the possibility of prohibited items cannot be ruled out. Either way, this is the basic nuts-and-bolts of security screening.
In FlyerTalkWorld, each one of these different types of screening are referred to as "retaliatory screening."
