Mmmmm... Beeer! lol
You'll find a lot of stuff on the internet. What you'll eventually come to understand (sooner or later) is MOST of the information about cannabis was created by people's observations. The downside is, most people are not growing in an optimal environment, so many, many, MANY things will seem to make improvements when overall they don't. When those techniques are used in grows with superior environmental controls, they don't make a spit bit of difference except sucking up expensive man hours and other resources.
That being said, it won't hurt the plants and the extra water from the ice might help with a wee bit more of a flush.