Yes probably they can guarantee people want be claiming more than one airdrop per person, maybe they will be using KYC?
I think they will only airdrop to all Verified Accounts in an exchange and also its possible they will use this 2nd round airdrop as a promotion to trade sirx on their chosen platform.
But i hope they will announce on which exchange they are planning to launch the 2nd airdrop so everyone can prepare just in case they are not yet verified on their chosen exchange.