We are allowing everyone to join for now, but we may change rules for future airdrop
Keep in mind also that if we don't allow to join the second airdrop to people who joined the first one, it would be easy to create a new address and transfer 0.01 ETH in it
Why ever change the rules? It wouldn't be a good idea to disadvantage those who support the project from the very beginning. If you can find a way to disadvantage those who sell the coins right after receiving them then that's one thing and maybe ok, but not allowing loyal holders to participate in future airdrops is bad. If you implement that, I won't be happy and I'll sell my FUDD.