Why can Appointment Groups be deleted by students?

[Alex911]

Hi everybody,

I wonder why students can edit and delete appointment groups that I've created. 

When I test my appointment group with a test account as a student, this test student can edit and even delete the whole appointment group.

Actually I just want the students to see the "reserve/unreserve"-Button. When I look at this Guide, it seems to me, that students should only be able to see the reserve/unreserve-Button (and not the button for group details and the delete and edit buttons):

https://community.canvaslms.com/t5/Student-Guide/How-do-I-sign-up-for-a-Scheduler-appointment-in-the...

Is there any way prevent students to edit and delete my appointment groups? 

Thank you very much!