Confirming browser prefetching is causing deletes
Django class based generic views allow object deletion see the docs so if you are using them you get delete method for granted in every view even though you don't define (overload) it.
The approach you have taken seems correct. However I have another approach to find out the deletes. You can write a custom manager for the django model and then override the delete(). Put a logger there, the added advantage to this approach is that if any other django app or any one else tries to delete a row from this model then your custom delete() would be used.
You can follow this article about how to implement delete using manager or overwrite the delete function of the queryset.