To my understanding from various Q&A here on meta (reference at the end) every piece of code posted on a stackexchange site gets published under the Creative Commons License.
A user on codereview asked for a review of his code linking to his repository, without directly posting his code. Looking in his repository, at the beginning of every file there's a notice like this one:
# ---------------------------------------------------------------------------
# Copyright (c) 2012 Xxxx Xxxx (aaa@bbb.com)
# Distributed under the MIT/X11 software license, see the accompanying
# file license.txt or http://www.opensource.org/licenses/mit-license.php.
# ---------------------------------------------------------------------------
Since this user has been asked to directly post his code, I'm not sure about what consequences there might be if he was to do it.
Would his code be available under both licenses? CC here and MIT from his own repository?
Could he have trouble in the future?
Would there be a license infringement?
Update: The code is been directly posted (with the license notice).
Other meta questions I found that are addressing license issues: