I don’t recall any court case supporting such.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;
Don’t see any provision whereby one religions free exercise may compel others to commit or restrict otherwise legal expression. Can a Jew order me to keep Kosher?
How can she freely practice her religion if she cannot take her children to the pool without exposing herself and kids to lewd acts?
Furthermore, she has the responsibility to notify the authorities about these lewd acts has the first amendment right to protest using picket signs and a megaphone to warn the other good citizens about what happens in the park.