Are there any analytics collected when a user clicks "Close as a duplicate"?
- how many search queries did s/he fire before pasting the exact dupe id?
- did s/he click on "Related" questions?
- how many are there dupehammer-wielding users, how active (distribution by number of dupe-closed questions per user) and how successful are they (% of "close as duplicate" approved)?
This can be done because it's in the logs and is already allegedly exploited by the serial voting inquisition.
Discussion of this proposal - Award accepted answer reputation for finding duplicates verified by OP - would benefit greatly from quantitative information.