I have read conflicting reports, but it appears as though women do have the legal right to not have tan lines. EDIT: 513-897-3055 I rec'd confirmation that it is indeed legal, I believe the Summitt guidlines pertain to a different park board.
8.7 Public Indecency and Nudity: Persons appearing on
Park lands, waters, beaches, or facilities managed and/or
controlled by Metro Parks, Serving Summit County shall
not intentionally or recklessly do any of the following
under circumstances in which his or her conduct is likely
to be viewed by and affront others, not members of his
or her household:
(a) Appear in a state of nudity or expose his or her private
parts (Nudity means, without limitation, the showing,
representation, or depiction of human genitals, pubic area,
buttocks, or the areola or lower portion of the female
breast with less than a full opaque covering);