I've heard one of the only things that are safe in any amount is alcohol-free beer. Which leads to some funny images of our medical studies if that was the standard we held.
Beer is mostly water and your body can literally collapse from to much of it. I made a quick search and I didn't find anything that proves what you're saying.
Yeah, it was a word-of-mouth thing which I didn't care to follow up on. Given that beer has electrolytes and too much water kills by displacing electrolytes, it does seem reasonable to expect you could drink more alcohol-free beer than water though.