Out of the solutions you proposed, I only see using a plagiarism bot to be a viable way to combat this sort of disintegrity. We already have Spaminator downvoting plagiarised posts, but the problem is that it only downvotes if the plagiarised content was posted previously on HIVE.
I've seen a few vigilante people out there catching bad actors red-handed, but that is still not enough to catch them all.
I'm a little hesitant about those bots because once it starts downvoting, it doesn't seem to stop. It's a bad thing for people who turn things around. However, it is a good option in helping keep track of identified issues.
In fact, bots help a lot, but I've seen the spaminator act "wrong" for no reason too. But it's just a matter of programming. However, unfortunately it is a complex process. Hive is really advanced on this and has a lot more people watching, POB is still slowly walking somewhere. And for now, the surveillance process is the best we can do.