Recently, a question was asked. In an answer, it was explained that the question was a problem from the most recent Mathematics Magazine Problems section, and that the answerer was in fact the author of the problem.
[I did look at MM's June issue, and there the problem is:]
It's certainly not our responsibility to read journals and make sure that problems asked here are not problems in these journals. But it's also reasonable that, if someone points out that a question is from a journal, we treat it differently (whatever this difference may be).
Is it our intent to allow these questions here?