Why not? "TSA’s Layers of Security"

Here we continue our series on public comment on TSA's naked scanners (aka, AIT, Advanced Imaging Technology) during their belated Notice of Proposed Rulemaking (NPRM):

Commenters addressed the TSA layers of security discussed in the NPRM. A privacy advocacy group suggested that the layered approach discussed by TSA is not supported by data and, therefore, does not justify the need for AIT. The commenter also recommended that TSA revise the layered approach so weaknesses in security can be identified. Furthermore, a few commenters suggested that TSA focus on other security methods, such as profiling, interviewing, and “Pre-check” screening programs to identify dangerous individuals. An individual stated that the efficacy of AIT screening has not been scientifically proven. The commenter further suggested that since there are other approaches used by TSA to identify potential threats, AIT would be most useful as a secondary screening method instead of as the primary screening method A professional association, however, stated that because of the advanced methodologies of adversaries, technologies like AIT scanners are needed to secure air travel. The commenter suggested that techniques involving human intervention, such as Screening Passengers by Observation Techniques, the Behavioral Detection Officer program, and passenger screening canines would also be useful. Many commenters mentioned their support for the use of racial profiling tactics instead of AIT, and argued that such measures would be more efficient and effective. 

An advocacy group alleged that TSA’s “trusted traveler program” approach would weaken security because it can eliminate entire classes of passengers from AIT screening. The commenter recommended that TSA consider other, less invasive and cost-effective screening procedures that would allow TSA to implement AIT as a secondary, rather than a primary, screening tool. Furthermore, the commenter suggested that TSA enhance layers of security by testing canine bomb detection, face recognition, and explosives residue machines, in an effort to reduce the need for AIT scanning.