In this answer, there is a copyright notice at the top of the code snippet. Should copyright notices be removed from code snippets?
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Your reaction was the appropriate one: enquire whether the copyright notice should apply (in which case the post needs to be flagged so that a moderator will delete it), or whether the code is released under the CC license (in which case the copyright notice is wrong and should be edited out).
In this case, since it has been established that the post was not made in error and the CC license stands, the license notice should be edited out. (Not the copyright declaration, which is effectively an attribution.)
Section 2 of CC Wiki states:
This can be interpeted as saying the user who posted the code may exercise copyright over it.
However Section 3 then states:
So a distinction needs to be made between a copyright notice and the licence granted by posting on this site. This particular user has a habit of including this text in his answers (here and here). If he is going to continue including copyright text in his code samples (IMHO he has every right to do this) then he should also be asked to add a line or two to make the licence clear and obvious, so potential users of the code are fully aware of the distinction.