Possessive

I'd use the possessive.

The boys don't own the boys' restroom, either.

In both cases, the "thing" may be thou

I am also one of the school that thinks the apostrophe is needed. Some people might claim, in cases like this, that the sense is not really one of possession -- but no one would say "Women Tennis" or "Men Tennis", which suggests to me that those people are subconsciously misunderstanding the plural "s" as automatically indicating a possessive.

I may be wrong, but intuitively, I am leaning toward "girls' tennis" or "women's tounament" (tournament).

I think your point about "Women Tennis" is right on.

You may feel that I'm "pestering" you, MrWordy, but I'm intrigued by your sentence,
"I am also one of the school that thinks etc."
If you are one, then you're "one of them," and "school" is a collective noun.
I think it could go either way - the school think, or the school thinks. But once you commit to it's be

AvangiWhat are your thoughts on this?

Hmm. I think that logically you have a point. On the other hand, even looking at it with your comment in mind, "one of the school that thinks" does not stand out to me as being wrong. I'm not really sure why, and perhaps it does to others.

Thanks for the answer, MrWordy. My first reaction was instinctive, and I tried to figure out what could be bothering me about it.