These airdrop rules get more and more ridiculous. Who would link 5 friends on facebook? Even if I would - I certainly don't have 500 friends on there. Not gonna sell my friends for an airdrop
I quite agree with you that the requirements for airdrop these days are getting more tasking that most of them can be termed bounty rather than airdrop because airdrop should be freely given - you don't need to do any task at all. I shared the same thoughts with until I saw how airdrop hunters ruined PlusCoin to the level that they have not been able to get out of it. Same goes to a lot of coins with easy airdrop application requirements and task. Times has changed and you have a lot of scammers participating in one airdrop with more than 50 accounts, most of which are not their account but details gotten from previous airdrop/bounty spreadsheets that was made public. You have to perform some of these task to confirm ownership of the account you are applying with. Even at that, a lot of the cheaters are scaling through these procedures but it will reduce the rate of cheating to a reasonable level.
To WebRun developers, KYC process has proven to be the best way to prevent cheaters from claiming airdrop coins/token with multiple accounts nowadays. It worked very well for PolyMath project to name but a few. Please consider that option