I saw some videos on youtube so in general it's a pure ponzi , but still most likely that airdrop account doesn't belong to them
you can leave a negative feedback in their thread so new users won't fail for that , but I doubt that people who participate in airdrops even read the threads

anyways nothing to worry about , you just need to create a useless email and use it only for the drops so you can't worry about someone getting your email and start spamming you