[link|http://atheism.about.com/library/decisions/religion/bl_l_GoodNewsMilford.htm|This] court case seems applicable here. From atheism.about.com:

Background Information

In August of 1992, the Milford Central School District adopted a policy allowing district residents to use school facilities for "holding social, civic and recreational meetings and entertainment events and other uses pertaining to the welfare of the community, provided that such uses shall be nonexclusive and shall be open to the general public," and otherwise conformed to state laws.

The policy expressly prohibited the use of school facilities for religious purposes and required that applicants certify that their proposed use complies with the policy:

School premises shall not be used by any individual or organization for religious purposes. Those individuals and/or organizations wishing to use school facilities and/or grounds under this policy shall indicate on a Certificate Regarding Use of School Premises form provided by the District that any intended use of school premises is in accordance with this policy.


The Good News Club is a community-based Christian youth organization open to children between the ages of six and twelve. The purported purpose of the Club is to instruct children in moral values from a Christian perspective. It is affiliated with an organization known as Child Evangelism Fellowship, which is dedicated to converting even the youngest children to their brand of conservative Chrsitianity.

The local Good News chapter in Milford requested use of school facilities for meetings, but was denied. After they appealed and requested a review, Superintendent McGruder and counsel determined that...

...the kinds of activities proposed to be engaged in by the Good News Club are not a discussion of secular subjects such as child rearing, development of character and development of morals from a religious perspective, but were in fact the equivalent of religious instruction itself.


Court Decision

The Second District Court upheld the school's refusal to allow the club to meet.

The Good News Club's sole argument was that the First Amendment dictates that the Club cannot constitutionally be excluded from use of the Milford Central School facilities. The Court, however, found in both law and precedence that restrictions on speech in a limited public forum will withstand First Amendment challenge if they are reasonable and viewpoint neutral.

According to the Club, it was unreasonable for the school to argue that anyone might be confused to think that their presence and mission were endorsed by the school itself, but the Court rejected this argument, stating:

In Bronx Household of Faith, we stated that "it is a proper state function to decide the extent to which church and school should be separated in the context of the use of school premises." ...The activities of the Club clearly and intentionally communicate Christian beliefs by teaching and by prayer, and we think it eminently reasonable that the Milford school would not want to communicate to students of other faiths that they were less welcome than students who adhere to the Club's teachings. This is especially so in view of the fact that those who attend the school are young and impressionable.


[...]

The Supreme Court reversed the above decision, finding that by allowing other groups to meet at the same time, the school created a limited public forum. Because of this, the school is not permitted to exclude certain groups based upon their content or viewpoints:

When Milford denied the Good News Club access to the school's limited public forum on the ground that the club was religious in nature, it discriminated against the club because of its religious viewpoint in violation of the free-speech clause of the First Amendment.


Significance

The Supreme Court's decision in this case ensured that when a school opens it doors to student and community groups, those door must remain open even when those groups are religious in nature and that the government will not discriminate against religion. However, the Court provided no guidance to help school administrators in ensuring that students do not feel pressured to join religious groups and that students do not get the impression that religious groups are somehow endorsed by the state. The school's original decision to ask such a group to meet later seems, in light of that genuine interest, a reasonable precaution.


Cheers,
Scott.