Interesting point. This would be like moving your BTC after every BTC fork coin (bitcoin cash, bitcoin gold, bitcoin private, etc). Personally, that may be overkill. If you're concerned, you can always move your EOS before doing anything for a fork or airdrop (I covered this 9 months ago here). But you're right, if there are multiple drops, you'll endanger something (even if you move your EOS) unless you create new EOS addresses each time.
That said, I'd never EVER participate in something that required a private key. There are many other ways to do this including signed messages.
RE: Evolution Airdrop - May 10th