Invisible is not the same as "see through"

This is why I never bought those X-Ray glasses advertised in the back pages of comic books.

There is a technology using terahertz waves that work the way those glasses claimed to and the images are hardly erotic. They show people squeezed into their clothing, mashed up as if they were against glass. They also show genitals, which may make people less willing to be subjected to them. They're like a strip search.