Its happened a few times to me lately. I mostly use my phone, and i go to upvote a deal , but mistakenly hit the neg vote instead. Then I immediately revoke (before I get pwned lol) but I can't then re-vote.
I think there should be a timer before a vote becomes persistent. I fully understand why the revoke doesn't normally allow a re-vote, but doing it within say 2 minutes should be allowed, to cover fat finger syndrome.
/discuss.
I agree completely on being able to change your vote, but I'd go further, and allow people to always change for much longer, rather than just 2 minutes.
Two recent examples where this would be warranted: 1) the OXY samples freebie that was withdrawn, after they had collected everyone's details, around month back: http://www.ozbargain.com.au/node/75265 ; 2) the Progear eBay bikes that got lots of plus votes, but which have recently been found to have an incorrect part fitted for the number of gears, so they can never operate correctly across all gears: http://www.ozbargain.com.au/node/78142
The bottom line is that often it can take a while to genuinely know whether a deal was good or not; and people should be able to adjust their votes based on the most up-to-date information.
Last time I asked about this in the site discussion forum, the mods replied with concerns about wildly fluctuating vote counts. I strongly suspect that won't happen, except in cases where important new information becomes available - such as the above - and in those cases, it would be entirely justified.