I have heard of it. I was helping a former roomate do a paper on Marijuanna. During my searches for marijuanna overdoses, I found numerous cases of water intoxication resulting in death (overdosing on water).
Hmmmmm OMGoodness! Years ago while still in the Navy, we had just left Jamaica where pot was good, cheap, and everywhere the Captain gave a surprise urine test to EVERYONE.
For those, including myself who indulged in the Jamaican culture were told to pass the test we should consume water like there wasn't going to be any tomorrow.
Drink water, GO, drink water, GO, drink water, GO till you really were'nt passing anything into the little cup except water. I swear I must have drank 5 gallons within a 2 hour time.