I would not consider that to be Plagiarism, at least not in the sense that gets you banned around here. The intent of the anti-plagiarism rule is not to prevent this kind of activity.
Also, receiving permission to use content is not relevant to if a person will get banned when a person plagiarizes content.
So what? His trust rating is representative of his personal experience with the exchange. They were a good client to deal with from Hhampuz's point of view. [...]
Here is the description of a positive rating:
Positive - You think that this person is unlikely to scam anyone.
Having a positive trading experience does not appear to be sufficient to warrant a positive rating, according to the above description. When you leave a positive rating, you are saying the person is unlikely to scam anyone.