Technically, how is OmiseGo deciding which Eth wallets to AirDrop to?

I understand they took a snapshot of the blockchain and will airdrop OMG to any Ethereum wallet with 0.1 or more Ether inside. How did they take this snapshot? Have they released a list of wallets they will airdrop to?

Also, they state they will avoid AirDropping to exchange wallets, how do they determine if a wallet is an exchange wallet or not? I am more interested in this on a technical side. Does the wallet have some sort of naming schema to identify as an exchange wallet or will OmiseGo have to talk with each exchange to determine this?