I apologize if this question has already been asked but I've searched high and low and not found an answer. Commonly, on SO and many other Stack Exchange sites, when I see a post flagged as a duplicate, spam, off-topic, and so on, someone will post a comment like "Off-topic; belongs on Server Fault or possibly Super User". Is this good practice? Should this be done? Is this something the flagger should do after submitting a flag? To me it seems a bit offensive and could garner dispute from an argumentative poster, but that's just my opinion.
As a quick example, a comment like this can be found here: setting up phpMyAdmin with WAMP server posted by a Mr. Jim Garrison.