I no longer plan to participate in the KDP Select program once my current contracts expire due to erratic and chaotic accusations of plagiarism.
Piracy is a huge problem and is often much more coordinated than authors realize. The even bigger problem is Amazon's unintelligent, punish-the-author approach to managing copyright issues. The pirates are laughing all the way to the bank while the authors are destroyed.
How does this happen?
When you take advantage of those 5 measly free days that Amazon uses to lure authors into the KDP Select program, so do the pirates. They come through, scrape your story, repackage and resell it on Amazon and all over the internet. (Hell, sometime they even shell out a few bucks to buy your book in order to steal it.)
Which results in Amazon accusing YOU of plagiarism once they find the plagiarized content. (Please, for the love of books, register your copyright!)
Amazon has been known to only give authors one day to respond to their accusation--better hope you're not sick or in the midst of a power outage or traveling. Even if you respond and prove you are the copyright owner, they have also been known to suspend, not just the book in question, but your ENTIRE account.
Once that happens your books' rankings are dust. Any momentum you've built up is gone and you will be starting over from scratch.
This is happening to authors right now. People are losing everything they've built. All for 5 free days and a buck something per lend.
I don't know about you, but the benefits of the KDP Select program are nowhere near enough for me to assume that kind of risk.
KDP Select gives Amazon way too much power, power they are abusing with draconian impunity.