diff --git a/AKModel/availability/models.py b/AKModel/availability/models.py
index 35814ee06d2bf49fe9416710c71cbebbb4fc7bb4..27a6c2287fd804dbf0f6c9c3d52b725f4afeb18c 100644
--- a/AKModel/availability/models.py
+++ b/AKModel/availability/models.py
@@ -293,7 +293,7 @@ class Availability(models.Model):
         #       event end + 1 day
         full_event = Availability(event=event, start=event.start, end=event.end)
         avail_union = Availability.union(availabilities)
-        return not avail_union or avail_union[0].contains(full_event)
+        return any(avail.contains(full_event) for avail in avail_union)
 
     class Meta:
         verbose_name = _('Availability')