CoreyCole: I actually failed the first test in my first play-through, and was not able to take an elective. That's perfectly okay; it gives Shawn more time to practice in the afternoons. However, a test too challenging for the co-designer seemed a bit harsh, so I made the correct answers a bit clearer, and lowered the minimum passing score.
jorlin: Dear Corey, when I meet Joel Kyro at day 31 I see no option anymore to buy the access code to the ghost fence. Is this intentional?
You have to know you have a problem before you can find the solution. If you've tried to get through the door without knowing the password, you can talk to Joel and get it (choose the "No Clue" option at the door). The conversation on day 30 bypasses that, as Joel will bring up the topic himself. But if you miss that conversation, you need to find the password-protected door before you can ask Joel about it.
I'm fine-tuning this a little for the patch, as in the current version you might be out of luck if the conversation comes up when you're broke. So thanks for asking about it!
Joel, by the way, is not the only entity in the castle that knows the correct password. However, you will always need to try to open the door before anyone will help you with it.