@Andy: They are legal if they're private universities, I believe.
And I didn't mean to imply that this whole thing about asking for information had actually taken place. It hasn't (as far as I know), just that it's being considered because there is a law in place in California that would allow them to do it if they choose to, though it would all be voluntary.
Personally, I don't like the idea of the information being attached to a person's name. Informal polls are good enough, I think. Plus, if you're in high school and applying for school you might not realize that it's pretty easy for your parents to review your applications and if you aren't out to your parents but plan to be if you go to college then you might inadvertently out yourself to your family.