i wouldn't worry about it. its just water. only thing i'd worry about is some hacker or something. i had that happen to me while trying to buy tracfone minutes from their site. transaction wouldn't go through. then 3 weeks later a 138$ charge showed up on my credit card for some stuff i didn't buy from a website i have never been on.
btw, if u are ordering bac h2o from a rc comp, i'd almost bet my left nut that they are selling u plain old distilled water.