You see, I once gave an open-book, take-home exam in a course I was teaching as part of a graduate practicum. For six weeks, I taught 8th Grade US History at Honey Creek Junior High School. I gave the kids the exam, but I told them they could work together. They could look everything up. They could ask their grandma for answers. I didn't care. But beware of pooling your ignorance, I said. Sure enough, I found quite a number of tests with identical answers. They were also identically wrong.
You can teach people facts, but you can't fix stupid.