I've spent my whole life under the impression that was a well-known myth of science. An old wive's tale. Silly, unscientific people fill their ice cube trays with hot water under the mistaken assumption that it will freeze faster that way. But people who understand science know that the hot water needs to become cold water before it becomes frozen water, so starting with cold water will give you a head start and will get you to frozen water faster.
For 40 years I've been told that the "hot water freezes faster" thing is a myth.
I feel that this "contest" is meant to be a joke.