Curation “gamed” through unvoting?

I was thinking about the feature of unvoting and its game theory extensions.

1. No unvoting

Supposing that no unvoting exists, then someone who cast a vote on an article which was provably fake or copied, cannot take it back. So in this case, there is plenty of incentive to cheat the platform through fake content. There is also fear of voting / reservations to upvote legit content without doing due diligence (too much effort, curator might skip voting altogether).

2. Unvoting implemented

If unvoting does exist, then there are two main cases.

a) After unvoting, the voter gets back their voting power

b) After unvoting, the voter doesn’t get back their voting power

In case (b), the voter/curator would be penalized if he acknowledged his mistake. Thus it would be in his interest to preserve an upvote, even in fraudulent content – otherwise he would lose money.

Case (a) is where it gets interesting. Case (a) is someone unvoting and getting their voting power back.

Supposing curation reward split takes place between 15m and 30m after a post is created, then we have the following situation:

- Curator votes in the 15 min mark

- Curator sees the votes accumulated till the 30 minute mark or later

- If enough rewards have been accumulated he retains the vote, otherwise he unvotes so that he can vote something else with better rewards

The process can probably be automated through a script – which makes it more problematic.

3. Fixing the issue

I tried to think how one can have solution 2a (unvoting allowed / user gets back his voting power) but without the gaming. 

Disallowing unvoting isn’t good – it’s a regression. Allowing unvoting but not giving the voting power back is also problematic due to incentives because then why would someone unvote. So, what to do?

I ended up with the following duct-tape solution: Limit the number of unvotes one has during 24hrs. Perhaps one unvote per 24hrs is OK. Or it could be slightly variable for witnesses/large curators who cast a lot of votes, allowing them to make a few more errors. 

If anyone has any better idea, or if my rationale is flawed somewhere, please contribute to the discussion.

Thank you...