Plagiarism is not a sin, nor a little mistake, it is simply against forum rules.
That probably wasn't meant in a religious sense, just sayin'.
I don't have a problem with plagiarism offenses being caught years down the road, but the deleting and reporting of posts for minor violations is unnecessary IMO. On the other hand, what does it matter? If someone's post count goes down because of very old posts being deleted, what's the worst that could happen? I don't think many members are going to get busted down in rank because of that, nor would they lose money in a sig campaign (assuming the campaign manager doesn't just look at post count).
User x plagiarized 5 years ago and it was his 5th post at that time.
It's forgivable.
I'd tend to agree. One instance years ago shouldn't necessarily result in a permaban if the member is otherwise an asset to the forum. That's just my opinion, however.