Bring the Answers to the Test & Get 80% - not as easy as it sounds

I let the students bring in one page of notes handwritten (front and back) to each test. If they bring the notes the most they can get is 80%. Usually about 3 or 4 students bring the notes. The notes they write from a study guide that is exactly like the test except I will change the order of the questions, so they can't just memorize a list of answers with no relation to the question. They can copy down every question with every right answer and bring it to the test, though.
I just finished grading 2 tests where the students took the time to make a page, front and back, of notes and brought it in to the test. The 7th grader was taking a multiple choice test. The study guide was multiple choice, but I changed the order of the questions from the study guide. The student missed 7 out of 16. The 6 grade test had 20 fill in the blank questions. The 6th grader, with a page of notes front and back with all the answers, missed 16 out of 20.
It is a little mind boggling how that happens.