Would the TSA be stupid enough to install a system that could detect criminal activity, i.e. concealed explosives or weapons, and not provide a means to save the evidence obtained that led to the detaining for suspicion of criminal activity? They would actually destroy the evidence of probable cause? They would initiate an invasive body search with photographic evidence that is not capable of being retained?

Yes, I think they may be this stupid, but in this case I can not believe they were. It is incredulous to suggest that the data is not capable of being archived in specific situations and on demand.