Be care to keybase airdrop that promised 500 xlm. Is a scam.
I don't join bounty airdrops, that is why I don't know this one, but regarding about your concern, it is just an airdrop, which is free if you follow their rules to receive it (don't requires any amount of money), if you don't receive it, then try another airdrops, there are plenty of them in the bounty section, crying about it because it is a "Scam" makes you look so desperate about airdrops, even it is not totally a scam.
Pity him. He's crying because he did not receive his airdrop or not received yet because it is from Stellar and many knows what value it contains. It is not just an ordinary airdrop, its partnership with keybase and github took long to make the event not taken to be granted that is why most of asian countries are not on the list of qualified users because of its historic matter where dummies and multi-accounts are present. This is false accusation since I've been seeing people flexing their free xlm came from keybase, And I heard
( maybe true or not) that some people bought a github account ( a year old) just to qualify for this airdrop.
Wait for a day or two, if you still not able to receive the airdrop coins you must have been disqualified for some reason.