Forgetting to cite a source is something anyone could do, and in Mpamaegbu's case I think it might be the truth. I just posted my opinion about it in the Report Plagiarism thread where it was uncovered. If that turns out to be the only instance of Mpamaegbu not citing a source, then I'd probably give him the benefit of the doubt if I were the manager of the BestChange campaign. As I said in my post, I'm fairly certain Mpamaegbu knows the consequences of plagiarizing and that a good number of members are hard at work sniffing out examples of it.
Well, Mpamaegbu got banned but I think he should appeal the ban. I know I just recently complained that plagiarists don't get banned after multiple reports but can't we just find a nice cozy middle ground. There is enough reason to believe that he didn't intend to claim the text as his own.
I bet he now regrets joining BestChange at all, as he could have continued to live happily in the Roobet campaign and no one would have been any the wiser.
Anyhow, back to the topic. How about introducing three strikes rule? First strike - a warning, second strike - a temporary ban, third strike - a permanent ban.
In essence, this would eliminate serial plagiarists and give those who inadvertently plagiarized a second chance.