Will I be banned for it in Fortnite?
Is that stream sniping
A skin contest is not from Epicgames so you can't be banned either.
No, streamsniping is when you intentionally look in the stream where the person is, and those are costum rounds, so why should you be banned?
But I didn't cure my mate at Skincontest
Yes, that doesn't matter at all. You are only banned if you hack or write insults in the chat.