Sometimes I see a highly voted excellent question on the Unanswered list and have some useful things to say that fall short of fully answering the question. But if I leave an answer with my partial thoughts, and someone upvotes it, then the question disappears from the Unanswered list and the odds that someone else will come along and give a complete answer decrease.
I'm thinking of writing "PLEASE DON'T UPVOTE THIS" at the top of such answers, with a link to this meta thread. Does anyone see something wrong with this plan?
Of course, another solution would be for math.SE to add the ability for me to declare that votes for my answer will not remove a question from the unanswered list. I believe that upvoted CW answers do remove questions from the list, so CW mode wouldn't help.