I've come across numerous ban appeal threads, but not all of them result in unbanning. So, my question is this, What if some members don't intentionally plagiarize content but still find themselves in that category?
I would say it depends on the length of text considered to be plagiarism, and the commonality of the text itself... For example, the phrase "A bird in the hand is worth two in the bush" has been posted on the forum dozens of times and as we all know its a pretty common expression. In using such expressions, nobody accuses the poster of plagiarism.
Plagiarism is more reserved for directly copying the original thought of others.
An interesting question that arises from this is "What is the shortest length of text in a post that has ever resulted in a poster getting banned for plagiarism?"
AFAIK, the length of plagiarized text needs to be at least 2-3 sentences long for the mods to take action. The chance of somebody randomly writing 30 or more words all in the same order as previously written by somebody else is very, very low.
For instance, Google returns zero exact matches of four words of your post, "don't intentionally plagiarize content". So generating 2 or more sentences in the exact same way that anybody else ever has is extremely unlikely (and of course, it depends on the context, whether they are referring to something extremely common or not).