The shares technically last forever so you will keep getting votes.

I don't think anyone will get downvoted just for having old shares.

Its the people who vote for their accounts too much that need to worry. You get around 1200% a day. If you are voting sbi comments and posts with more than 300% (three full votes a day), its probably excessive. Combine it with sending them a lot of steem to get shares using @ for your alt or buddy who is buyig you shares, and delegating them most of you sp...we end up seeing people who maybe should reconsider their actions.