Yeah Bitfinex has a method where they consolidate all of their users votes into a handful of proxy wallets. I'm not 100% how it works since i'm from the USA we are not allowed to use Bitfinex. But from what I hear they have a voting page for EOS and they submit the votes on the users behalf. However, if I was a Bitfinex user I would transfer my EOS to my own wallet where I hold the private key. And then vote. Just to be 100% sure my votes were counted correctly.