Anyone has a right to hire a school facility to use for their meetings as long as they are not doing anything illegal. Religious groups are just doing good for people and good for society. We should encourage them to use schools because some kids want to learn about religion and are not given the opportunity otherwise.
Anyone has the right to use the public school facilities after hours, whether it be churches, homeschool groups, a corporation having business meetings, etc. WE paid for those school with our tax dollars. The separation of church and state simply means that the state (government) can not force a religion upon people. It does NOT mean that the state (government) should not work with religious organizations in the manner of letting them use the facilities.
This is perfectly fine as long as the school allows all religious groups to use it's facilities. It can't limit it based on the religion. That would violate our right to freedom of religion. It also can't force students to attend or give favor to one over the other. If you allow one persons christian group to be mentioned on the announcements, my satanist group must also be mentioned.
My argument regarding this opinion is that if the facility isn't being rented in order to be used for religious reasons, then I will have to say that is it in fact illegal for a public school to allow a religious meeting to be taken placed in school, even if it's "after hours". Tax payer money is being used to hire the teachers, the principals, the members of the school directors, the school building, and paying for the schools utility bills. Since this is the case, using our public school building as a place for religious worship is illegal and goes against our constitution and bill of rights. If the religious group rents out a facility within the school to have their religious session, then this won't be illegal, and I don't have a problem with it.
I would agree and argue that if the public school is requiring reasonable rent or use fees for religious organizations to occupy facilities temporarily then there isn't an issue. However, installing permanent or semi-permanent signage to "market" religious events taking place at that facility crosses the line to suggest endorsement of the school/district for a particular religious group and therefore is illegal.
Schools which allow religious groups to use their facilities for their own purposes will be seen as religious schools. Religion and school should be firmly separated. It is unfair to use religion in a facility for education. This is why no school or educational facility should be used for religious purpose.