If enough writers use a given object or situation in enough works, we start to recognize and understand the range of possible meanings. They don’t have to say, “Hey, pay attention! It’s raining!” They can simply make it rain and we’ll do the rest. The writers don’t even have to think about it; it can rain because that’s what the plot demands. We can figure things out from there.
I think this translates to: authors can do whatever they want (bonus points if it's a recognizable event) and the readers have to figure it out.
