First of all, I believe that for serious offenses such as scams etc. we should have a way to exclude such members from the forum.
The best way of "excluding" a proven scammer here in the forum is through the trust system and flags created under him. Bans on the other hand are out of the picture since the forum is trying to avoid moderator abuse from varying opinions on each cases. Even though compared to plagiarism where money is loss I believe this is the best way right now of handling scammers in the forum.
But, what about some other, no so clear cases like plagiarism?
I think we could already see different standards for solving this problem in the forum so far.
Some cases are resolved very quickly and easily, even in a few days or hours but some other cases have not been resolved in months, without clear reasons.
We cannot really have a set standard when it comes to handling members who have been dealt with a plagiarism permaban, by giving them a criteria on how they could post again in the forum would simply make plagiarizers have an easy way to come back in the forum and post again. Even if they have "learned the lesson" from the ban it simply makes plagiarism a not so serious case in the forum anymore especially for the members who have established their name in the forum for doing a good job.