ubiq, the Jews won in court and had the Eruv ban in Westhampton overturned because the ordinance banning the Eruv was an unconstitutional interference of government in religion. There is no roundabout way to make a ban that is intended to inhibit a religious practice be constitutional by pretending the law was enacted for an allowable secular purpose when the true intent, even if not admitted and outright denied, was religious based discrimination. It is unconstitutional on the face of it.
You are are asking about hypothetical laws that can’t be legal any way you cut it.