You forgot
8. It's toxic.
I have a seven page (CYA Liability Lawyers Gone Wild) MSDS for Ultra Pure Lab Grade Water which lists an LD-50 for ingestion. The lethal dose for a grown man turns out to be about 5 gallons. Obviously the liquid limit is there so a suicidal passenger can drink every 3.4 ounce bottle on a plane and not hurt himself. TSA, Always Only Thinking of Our Safety™.