Some airdrops require personal info from their users like government approved ID proof, a selfie with it, contact number, email, address etc. Does this information really required? How to know if somebody is scamming you for asking this kind of information?
I usually avoid that kind of airdrops, it is not worth to give all those information about yourself for a few bucks worth of crypto.
Good airdrops are stake based, like when you get a founding stake in the project, like XEM or Elixir.