Air drop means free money if you receive the tokens
Most of the air drops doesn't receive tokens,
Personally I have received about 10% - 20% of tokens from airdrops
Luckily some tokens have gained me considerable profits
Some scammers use airdrops to get our Private key,
Do not give your wallet private key at any circumstances..
yes there can be some hidden agendas. some of come to collect all personal details of people which they can resell to marketing companies and earn profit. So before applying for any airdrop a simple study is very much valuable.