Yes, this was actually adjudicated.

A Montgomery County court yesterday brought peace to the many Marylanders who believe that mooning is an appropriate form of expression. Ruling in a case of a man who bore his buttocks during an argument with his neighbor, the presiding judge noted that mooning is not illegal in Maryland, no matter how unfortunate the behind being exposed is. He stated, according to the Post:

If exposure of half of the buttock constituted indecent exposure, any woman wearing a thong at the beach at Ocean City would be guilty.

Now that’s some solid legal reasoning, worthy of becoming precedent. The fact that this actually got to the courts is about as foolish as when Virginia tried to outlaw the wearing of low-riding pants.