[themafia]

> the starry-eyed "free web"/"open data" idealists.

I love it when the people who just want to use technology to benefit humanity as a whole are dimly regarded as "starry-eyed idealists."

> because it will separate the site from its users, sites will obviously not do it.

Sites don't generate their own users. Users must discover sites. This allows a third party to dictate terms to them. Which we already know happens.

> especially if the water is obvious poison.

Alcohol exists. I think you might want to put away the "perfectly rational" assumptions about humanity.