UPD: try to make trainers happy. registration is is now hex coded. made

clear, that attendance is not guaranteed.

dav_registration/models.py

@@ -71,16 +71,33 @@ class Registration(models.Model):
                                                   verbose_name=_('Einwilligung zur Datenspeicherung'))
     purge_at = models.DateTimeField()
 
+    @staticmethod
+    def pk2hexstr(pk):
+        return hex(pk * 113)[2:]  # 113 has no meaning, but it produce nice looking hex codes.
+
+    @staticmethod
+    def hexstr2pk(hexstr):
+        return int('0x' + hexstr, 0) // 113
+
+    @property
+    def hexstr(self):
+        if not self.pk:
+            return None
+        return self.pk2hexstr(self.pk)
+
     class Meta:
         verbose_name = _('Anmeldung')
         verbose_name_plural = _('Anmeldungen')
         ordering = ['created_at']
 
     def __str__(self):
-        return '{number} - {name} ({created} - {purge})'.format(number=self.event.get_number(),
-                                                                name=self.get_full_name(),
-                                                                created=self.created_at.strftime('%d.%m.%Y %H:%M'),
-                                                                purge=self.purge_at.strftime('%d.%m.%Y %H:%M'))
+        return '{eventnumber} - {name} ({registration_id} - {created} - {purge})'.format(
+            eventnumber=self.event.get_number(),
+            name=self.get_full_name(),
+            registration_id=self.hexstr,
+            created=self.created_at.strftime('%d.%m.%Y %H:%M'),
+            purge=self.purge_at.strftime('%d.%m.%Y %H:%M')
+        )
 
     def get_absolute_url(self):
         return reverse('dav_registration:registered')