I am writing just for share with you the solution I used for the scenario we talked about here: https://tri.be/support/forums/topic/booking-system-for-school-exams/#post-190730
At the end I used your plugin for add the events (in my case called exams) and for each user that want to take an exam I added a button “book now” on the single event page.
When an user click on “book now” button I create a new post (custom post type) that sync the event with the user and the teacher can choose if accept or deny the book request.
I used a custom post type because teachers want history for each user and they want add several custom info related to the exam. (for example: mark, exam status, attach documents ect.)
I hope this helps someone 🙂 Let me know your thoughts or if you want suggest something else.
Thank you for your attention!