If they charge for airdrop then it is a scam airdrop campaign. While there are some airdrop campaigns that actually payout after sending a fee, it's still a risk. They can be trusted if the project is popular and good. It is better to avoid such airdrops.
why take risks with tokens/coins that will be "shitcoin/token". I have never participated in Airdrop since 2018, everything will just be a collection that contaminates the wallet, some pay but the value is much smaller than the exchange fee. it's better to just avoid all forms of airdrops that ask for fees from potential coin recipients..
Not all coin from airdrop as collection in your wallet because many airdrop coin have higher price than ICO or bounty coin, just how lucky you are when receiving new coin from airdrop. I just have opinion during airdrop not need to send fee I will join all because get got lucky and bigger chance after joining many airdrop will get big chance with airdrop coin have higher price, I have miss with many airdrop and see my friend sell coin on higher price but now I will never for missing new airdrop again although look not potential, look what happen with bsc airdrop and how much coin raise to higher price.