it dilutes all your body's minerals like sodium and potassium and such. unless you either piss all the water out quick or take in the proper ratio of minerals/water then yes, you can kill yourself by drinking too much water.
i guess. thats how tight people are with thier money though, they dont want to go spend thiers would rather subject themselves to idiocracy like lets see who can drink the most water or going on national tv and be made a fool of. i feel bad for the kids