No it does not work.
First of all when the radiator is hot you can not open it to put ice in because of pressure and once you would put ice in it would melt and then be nothing but plain water in the system.
I think you misunderstood what you were hearing. They were probably talking about using Engine Ice which is a brand of coolant which brags that it can drastically reduce operating temps over using plain coolant. Does it do what it says? I have no proof one way or the other and I run plain old coolant