There are people who don't have any idea how bitcoin or similar tech works, everytime you send a transaction, the "rest" is sent to another address and if you don't register that address for the airdrop (or don't transfer back the coins to your registered address) then you won't get the airdrop. I don't know how people keep failing at it when weekly I see multiple posts showing to use coin control... the trojan is either sarcasm or just pure fud.