Fortnite skin contest how?

What you wouldn't expect otherwise with this platform lol haha, so I often see streamer doing a skin contest, but I always wonder how it works then that you all work together the same lobby or round is coming and do you know any tips or tricks on how to prevent streaming sniping in the skin contest?

Customgames, youtubers with a creatercode get a code where they can start rounds where you need a code to get in