They are probably adding some more features to prevent cheaters in joining the airdrop and they probably doing manual checks on all participants specially those users with thousands of down line to check for any irregularities so in the next airdrop we can expect a bigger cut in the 1 billion monthly allowance.
I agreed with Xcash team approach to manager their airdrops, and avoid falling into cheat efforts from cheaters, and bounty hunters. The amount of money (maybe in
BTC, tokens, or altcoins) the teams and managers of campaigns should work together to inrease the probability to get high effects from their airdrops. Giving away via airdrops is good thing, but it does not enough.