In ITC-LMS, the default setting for "self-registration" is permitted, but the setting (Permitted/Not permitted) can be changed by the instructors at any time. Students (enrolled students) can self-register to take a course or to cancel the registration freely while self-registration is set to “Permitted”.
However, when the self-registration is set to "Not permitted", students (enrolled students) will not be able to self-register for courses or cancel the registration by themselves. Even if self-registration is set to "Not Permitted", academic staff (instructors in charge) can register course participants (enrolled students and TAs) whenever they want.