yes ive encountered some of them lately as i recieved some emails that is related to airdrops but i dont usually sign up on other airdrop sites aside from airdropalert . the best thing you can do is to report those email and mark them as spam , so that you wont recieve them more frequently .
most people nowadays are using others information in order to sign up for bounties and airdrops . some of them are selling other infos so that they can send you advertisment to your email address and other accounts .