First: water in boat gas is quite common. Despite various protective strategies, the vents are outside the boat and spray, large waves, heeling in a corner, etc some water can go in the vent. In a watershow act called "skiaround" (skiers ski all the way around the boat) the driver tosses the boat from side to side violently to make this happen. At one time I put a separator tank in the vent line, and found I was putting about a qt a day into the tank. Eventually I moved the vent to the front deck of the boat.... better but water is possible. Outboards chuff and chug but amazingly still run. Isopropyl alcohol in the fuel soon clears it up.
Phase seperation: Occasionally happens with E10, often in winter when the water fraction becomes to great. Our local BP station had a tank go bad, many cars were disabled within a mile or two after filling.... including a brand new Toyota being filled by the dealer for the first time.
BP admitted that it happened there, (heck, people who had filled together found themselves stalled together) but there was a legal battle between the gas station and the terminal over who had caused the incident. It was in the paper here for weeks, the car owners had to tow, drain and repair their cars themselves while waiting for a decision on who would pay.
Storage: The NMMA (National Marine Manufacturers Association) has recommended E10 not be used for storage, when possible. Ethanol is conductive and greatly increases corrosion in the gas tanks. Car tanks have long since been upgraded to triple nickel plating and other things to help prevent this, many boats are not.... and are often older model years anyway.
OK, ski arounds: If you go to a professional waterski show you will certainly see someone do it. If you come to our watershows, you will see 7 people go around my boat all at one time. (the world record established in tournaments, is 8 around)
This trick also puts lots of water in the boat, and my blonde ropehandler becomes very wet, but decidedly more scenic!!