It's not uncommon to see in newspapers stuff like "homeowners insurance" without an apostrophe. It's not a mistake. The idea is that you can look at "homeowners" a descriptor and not a possessor.
But how, then, to explain Childrens Hospital Los Angeles?
It doesn't work the same way. While "homeowners insurance" could be insurance that pertains to homeowners, "childrens hospital" would be a hospital that pertains to children -- not childrens.
I also saw a reference to a Womens and Childrens Hospital.
I believe there's a strong trend in this direction. For some time now, publications and businesses have been seizing on justifications for omitting the apostrophe. They don't want to use these apostrophes, so they find reason they don't have to. But now it seems that, more and more, people aren't bothering with the "this is really a modifier" justification. They prefer no justification at all.
I'm not complain', mind you. And I'm certainly not trying to stop the trend. (I know how productive those little campaigns are.) I just don't know what it will mean when the dust settles. Will "womens" and "childrens" start appearing in dictionaries as modifiers? Will grammar books start to acknowledge phantom apostrophes (kind of like the zero relative you create when you change "I know that you like me" to "I know you like me")?
I just don't know.