Another solution to this problem:
People are voting to close as exact duplicate without leaving comments. Such votes are invisible to everyone under 3k. A comment is the primary way others can see that there's a duplicate until the question is actually closed. Until people are notified, the question may get answers that really should go to the primary question.
- When voting to close as exact duplicate, the system automatically adds a question comment,
Possible duplicate of -link-
- It would search the comments for the number of the duplicate, and if found it wouldn't add the new comment (ie, someone has already pointed out the dupe) but if not then it would add the comment. This will also repress extra comments as others add their vote to close, unless they chose a different dupe primary.
- The comment would be either under the community user, or the user that voted to close as duplicate
This would give us the same information we had when people manually marked questions with dupe info, and the same information we get when people comment on the question about the dupe. Automating it would make it a little faster and consistent.