My intention was only to point out that some things are free for moral reasons. Not every rule of society is a law per se, if some one asks you for a cup of water and you don't give it to them you're probably kind of a dick, right?

Its a social standard not only because of the very low cost but also due to the horrible things that happen to dehydrated people and the frequency that it recurs. http://en.wikipedia.org/wiki/Dehydration#Signs_and_symptoms

I suppose should have added the qualifier decent to society.