There are of course cases that slip through when it comes to plagiarism. It is greatly appreciated when community members spot them and bring them to our attention. These things happen not only with Curangel though.
When it comes to quality standards as it is hard to define what's a quality post, Curangel rules are perhaps not as strict as for some other groups. As long as curator has valued the post as original and providing some sort of value and are not plagiarism, they are fine. Since we are aiming for far and wide distribution and our vote is not yet astronomical it seems reasonable at the moment.