What about the guy who actually asked the question? this whole thing emerged in an askreddit thread in which someone asked what would happen if marines went back in time.
I'm pretty sure he doesn't get anything. Ideas aren't subject to copyright protection. Ditto for the people who made suggestions, unless Erwin copied text into his story.
Right. Writers are told all the time "I have a great idea. You write it and we'll split the money". I read of one writer's response "I know this boxer; you fight him and we'll split the money"
