Is there anything that can be done about a user who switches his answer to Community Wiki after receiving a downvote?
It looks like doing that clears out the rep loss from negative votes, but is that actually what happens? Did I just observe a strange case of timing between my downvote and a the user editing the answer to make it CW at the same time and just beating me to it by a second?
I don't doubt that some people mark their answer as community wiki to try to avoid rep loss from previous downvotes, but we should try to assume good faith. One could read the same action as the answerer saying, "okay, you guys are right, this answer sucks: please help me make this answer better."
In terms of clearing out any downvotes they had, that shouldn't occur. It's probably the case that your downvote and the community wiki flag was coincidental.
Just to clarify, you can't undo existing downvotes by switching an answer to community wiki.
The existing downvotes remain, but all future downvotes, after the switch, will not affect that user's rep.
I'll make my answers community-wiki sometimes when I'm arguing against a common meme on SO. In some cases you cannot avoid downvotes if you voice an unpopular tidbit.
Also on occasion, I'm posting an answer in lieu of a comment - when multiple issues should be mentioned, usually for poor questions. In essence the answer then amounts to an elaborate LMGTFY and a couple of onsite links. The last one I even declared an "faux answer" outright. (Incidentially that one even got an upvote, even if it didn't address the core question.)
Last note: "community wiki" isn't really what the name suggests. It's what people make of it. Unless there is outrageous abuse (and undoing downvotes seemingly doesn't work anyway), it seems unproblematic.
To me, CW has only one advantage, it permits a broader group of users the necessary privileges to edit something.
I use it when answering a question that might not suggest the same answer a year from now, or even a few months from now.
As far as I know (ICBW), the only way to remove down votes is to delete the answer and recalculate reputation, just like up votes go away when an answer is deleted and reputation is recalculated.
I don't see anything terribly wrong with people wanting to stop the onslaught of down votes while they fix their answer, but the best way to do this is just delete it, edit it, then undelete it.
To me, converting an answer with lots of down votes to CW is like saying "Ok, you don't like this answer? you fix it!". So, perhaps the best thing to do is just fix it if you can.
In my experience on this site, changing an answer to CW would have been a bad idea, even after 17 down votes - so they may just be hurting themselves through the conversion.
