There have been many examples of fraudulent airdrops. There are many more examples of honest and trustworthy airdrops which are essentially marketing schemes, but it is wise to always be a touch sceptical.
A common airdrop scam is to simply harvest email and KYC information. Free money from airdrops looks appealing, but if all you are doing is giving away your passport information then it's not such a good deal.
As with web wallets, you need to do deep-dive research on any airdrop you are considering — or ask us to do it for you. Module 2.12 talks through one specific example of this genre.
Please feel free to contact us with any questions.