by Colin Fraser.
In the Teacher Role there is the ability to change the short name of a course. The default is set to Allow, but you can change that by unchecking the permission box.
Go to Site Administration > Users > Define Roles > Teacher (or whatever Roles you want to change this on) and click the Edit button. Search for "short" and you should find the lines:
Change course short name
moodle/course:changeshortname
Checkbox is alongside.
Cheers...