So someone created a working bot to detect them?
I have no idea how he spots them but he does a good job.
Suchmoon is transparently one of the people who is reporting plagiarized posts (I am not sure if this is who you are referring to). She is transparently scraping posts in the forum and putting them in some kind of database, which is concerning for a variety of reasons, including the type of business she is in and her lack of integrity. She is most probably cross referencing posts in her database with some other database and/or with google/another search engine.
She also targets, in part specific members, and I know this because she was able to cite a plagiarized post that Redsn0w created from many years ago that was written in a thread with a very small number of posts, and the most recent post in the thread was also from many years ago. I would not make her a mod, and I think a decent number of people would leave if she was made a mod, or if it was discovered she was a mod.
All of the posts here are all public with the exception of a few boards? (No idea what they are, not the point) so if all the information is public anyway, why does it matter if its collected and saved or not? If you think anything you publicly post on the internet isn't saved than you are just kidding yourself.