Hi M Chico
You no need to worry a user cant see all event. Please read defination below:
- A User Event will only be visible by the user currently logged in (i.e. the one creating the event)
- A Group Event will be visible to a particular Group on the course (chosen from a drop-down list)
- A Course Event will be visible to participants on the course in question. Only users with the capability to manage calendar entries at the course level can add course events.
- A Site Event is a "global" event - visible in every course and on the calendar on the home page. Only users with the capability to manage calendar entries at the system level can add site events.
Note- Hiding event will not work for others if teacher hide it in one course i have tested it .