Temporary bans are the warning, but depending on the severity of the rule infringement, a given user may be banned permanently either through reiteration or straight out. Some have managed to get their permanent ban revoked, or commuted for a signature ban for a certain period of time, but those cases will need to be somewhat clear-cut or net positive with regards to the Forum. You can see some of those cases in this (non up-to-date) thread: [BAN APPEAL]UPDATE: Total table + Ban status (Need feedback from Global mods) .

Normally, simply not providing the source and being banned because of that, entails something else to begin with, and that is that the content posted is verbatim (total/partial) or slightly spinned at best. It’s true that in these cases, adding the link gets him off the hook, but the subjacent effort is pretty small to begin with, and sometimes on the rim of being deceptive to begin with.

On the other hand, if a person goes to the trouble to summarize, elaborate, question, criticise a given external content, writing his content in his own words, it seems a much more elaborate process, where the content created will be based, but with entirely different wording and depth, to that of the potential reference. That seems rather distant to any potential association to performing plagiarism. The link may of course be added, so others can read in full the basis, as a means to expand on.

Having said the above, since plagiarism is one of the main causes leading to a permanent ban, it has been mentioned multiple times before that getting the Welcome Message into motion and/or a warning in the textbox where we write our posts, may serve as a reminder. So far, these two ideas remain unimplemented.

Note: If one is banned, he should not be "starting all over from the scratch". A ban applies to the person, not solely to the account caught in the act.