Today I wrote the following email letter to an author who just submitted a manuscript and an accompanying cover letter to "my" journal:
Dear [Author’s Name],
I noticed in your cover letter the three names you suggested as prospective reviewers for your manuscript submitted to [My Journal]. A quick investigation reveals that these three people have all served as co-authors on prior publications co-authored by you and thus have a conflict of interest if they accept the review of your manuscript submitted to [My Journal].
I believe suggesting reviewers that have a conflict of interest cannot be considered good scholarly behavior and is even unethical. I have been lining towards rejecting your manuscript immediately, however this would harm the career of your current co-author, [Name Co-Author], which is not my intention.
From your cover letter I can also read that you are currently an associate editor for [His Journal]. I must admit that this worries me, as members of the editorial boards of highly reputed journals that use peer review should be members in good standing and thus refrain from creating and/or benefitting from conflicts of interest. I am pretty sure the Editor-in-Chief of [His Journal], [Name EiC], will agree with me.
In the interest of your co-author I will proceed with the review process of your manuscript. However, I hope you can assure me that this will never happen again.
I expect an acknowledgement of receipt of this message and, if possible, an explanation and/or reassurance.
Wouter A. Serdijn, PhD, F-IEEE
IEEE Transactions on Circuits and Systems-I: Regular Papers"