That's a funny idea. "Hiring" people to check airdrop applicants.

The best way imo is to connect multiple accounts so that you can't apply with your 389 BCT alt accounts. Telegram needs a phone number, for example. Most people have only one number and one Telegram account so that would reduce the abuse.
a telephone package cost $2-3
the only way to prevent abuse is the rank
or maybe they should require a retinal scan

Yeah anyone can buy a burner phone for a few dollars so that isn't much of a deterent. High rank is likely the best way because even if you created a million alt accounts, you didn't make enough posts on all of them to get to the high ranks. That would be an insane amount of work for a person.