The worst thing we've learned is that all we have to say is "we followed standard procedures" and we get a free pass, regardless of how egregious standard procedures or implementations may be.
When I have been patted down by TSA they are always careful to ask for my consent before they sexual assault me. Since I am past the age of consent I can give it to them. Here the TSA is relying on the parents to provide the consent to sexually assault their child. I don't think a parent can legally give that consent. If I were a DA I would charge both the TSA agent and the parent with criminal child abuse.
It's obviously not sexual assault under law, since the searches are explicitly authorized by law. Even if the searches as designed were found to be unconstitutional or contradicting other law, that in no way would subject an individual agent following that law to prosecution under the government that gave the agent the orders.