One of our teachers used a collaboratively built wiki for all students, where everyone could add their entries and files.
Unfortunately, someone deleted a lot of files from the Wiki file list, so that those pictures did not display any more.
Unlike for wiki pages, there does not exist a history for the File tab, so there is no easy way to restore those files.
To make matters worse, deleting files from a Wiki is not included in the Moodle logs, so it's not even possible to know who deleted the files.
There is also no permission tied to the ability for deleting files that I could take away from the student role, without taking away their ability to add files as well (mod/wiki:managefiles).
I made a tracker item with suggestions for improvement - please vote on it or add your input if you are interested in improving this: