Not all airdrop are scams and theft of personal information. Honestly, airdrop really wasted participants' time. I recently participated in few airdrops and have received their rewards. But the value is very small and there is nothing I can do about it .I can only hold them and hopefully one day it can raise prices.
If an airdrop start asking for personal information like name, id and passport. Its a sign that you have to turn away. But there are really some worthy airdrops. You just have to be lucky to find them all.