I've heard a lot people screaming scam because they ask for private keys. Well sure, anytime you expose your keys you are at risk. That's a given.  But what about this: Your ETH is in a normal wallet where you have the private keys. The fork occurs. You move ETH to different wallet. Then use the original keys in the now empty wallet to claim forked coin.

I mean if your wallet is empty, they can't steal anything.

Am I missing something here? Please enlighten me.