I'm not sure it would be responsible for anyone to pass along their vote or allow anyone to act as a proxy. This gives some users imbalanced voting power and leaves minnows at a disadvantage.

Who is more likely to get passed a proxy vote? Large accounts.
This may allow a single user with a bunch of followers to unfairly influence important decisions that would be better represented with one vote, one account.

If large accounts or personalities have a certain position on a particular issue they should have to campaign and blog their sentiment to the community and have them cast their vote accordingly, not cast hundreds if not thousands of votes for others. There are too many ways to exploit this kind of feature.