What part of the Big Sign Outside the Detention Facility Did They Not Understand?

You know, the big sign outside of every single jail, prison, and detention center I've ever been to tells me that I am subject to search.

Three girls, who were visiting a detention facility in order to avoid going to court for trespassing, were strip searched. It strikes me that the detention center might very well be within its rights in the search. However, when it made the visitors don dirty prison garb it probably crossed the line.