It's a stupidly dangerous idea, but one that might actually work if the outlet isn't a GFCI. Current is divided across all paths inversely proportional to their resistances, and tap water is a worse conductor than metal.
It's an inflatable pool. If you're not using it for more than a day or two, you can probably get away with using tap water if you drain it right after.
The salts and oils from human skin might be a different concern, however... (albeit they will be very diluted)