transparent clothing; strapless garments; any garment which exposes the stomach or any intimate area of the body, tank-tops; halter tops; dresses, skirts and shorts which are shorter than four (4) inches from the middle of the knee; garments with obscene logos; low-cut blouses; obvious lack of undergarments.Your guess is as good as mine. Those happen to be the clothing restrictions set by the U.S. Bureau of Prisons for visitors of inmates at federal detention facilities (PDF).
Diogenes at Off the Record on CatholicCulture.org wonders aloud: "So ask yourself: did the persons who presented themselves to receive the Eucharist at your parish last Sunday meet the prison decency code?"