I was lucky enough to get the update message "This question was closed, new answers will not be accepted" (paraphrased) while composing an answer to this question.
This is an extremely unpleasant user experience. If it were a conversation, it would be something like this:
A: So, tell me about your weekend
B: Actually it's quite a funny story.
A: Oh? Go on
B: Well, I met up with a few friends that I haven't seen for...
A: SHUT UP! Nobody wants to hear about your stupid weekend, we only care about work here.
I understand there are more than two people involved here, but the overall impression of the site as a user feels equally schizophrenic.
I feel like I at least ought to get some kind of warning that a question is being voted to close. Right now I get no signs at all, just a sudden message telling me to forget all about submitting that answer I spent a bunch of time carefully composing.
How do you think SO ought to handle this situation?