Occasionally I will find that a sub-optimal answer has been selected by the OP as the accepted answer, when a much better answer exists. Sometimes I feel responsible to down-vote the selected answer to offset this*, so future readers might get some idea that, while accepted, and not necessarily a bad answer, this may not be the best answer. This is most clear when the accepted answer has low or no up-votes and a better answer has several.
In some of those cases, the OP later unaccepts the inferior answer and accepts the better answer. I think that in this case (and probably others I'm not thinking about presently) it would be useful if this could reset the vote timer - allowing me to undo my down-vote (and maybe even up-vote) simply based on the fact that the accepted status has changed, without having to manually ninja-edit (or obvious-edit) the answer. In my opinion this is still something that has changed about the answer, even if the content hasn't changed.
It's easy enough to just edit the answer to reset vote timers, but then the whole anonymity thing goes out the window. And I usually screw up the ninja edit.
I get that I am no longer judging the answer on its own, but I think that the little checkmark attached to the answer becomes a part of the answer, as it can certainly influence how future readers perceive the answer. Especially those coming from other forums, like MSDN, where the best answer is often selected by moderators, not an OP who might not really be able to judge the best answer.