This is a plausible statement of the case. However, it hinges upon renting
the space to the group, where religiously affiliated or not. If the school board were to offer the use of facilities free, to any group, religiously affiliated or not, they'd be giving away the public nickel. Especially in the United States, where public schools are supported at the lowest level (i.e., property taxes assessed by township, municipality or county), if a school board attempted to offer their facilities to any group for free, they'd be a sitting duck for a law suit.