A nice temporary solution. It still however pins the downvote on the poster not the voter. With 493 votes it would be very difficult for someone to see or find a specific vote to erase. However by displaying the upvoted amount next to the name in the drop down for the first 20 votes, the offending amount of excess reward would likely be visible. There is plenty of room to put a downvote arrow next to the name that gave the excessive award, and remove any chance of curation reward to them with a down vote.
This would make the "Disagreement on Rewards" very plain. The poster has very little control over who votes except for the purchased votes. After a while any business that is repeatedly hit by down votes from one account will blacklist that account for abusing their system. A win for the people of steemit all around.