diff --git a/website/events/api/serializers.py b/website/events/api/serializers.py
index 3603529ecaa1860257cf8aaa956c9c8b9eaa3e16..98816baf4889ba3459f48cdda0e3cda8f2068d07 100644
--- a/website/events/api/serializers.py
+++ b/website/events/api/serializers.py
@@ -181,7 +181,8 @@ class EventListSerializer(serializers.ModelSerializer):
     class Meta:
         model = Event
         fields = ('pk', 'title', 'description', 'start', 'end',
-                  'location', 'price', 'registered', 'pizza')
+                  'location', 'price', 'registered', 'pizza',
+                  'registration_allowed')
 
     description = serializers.SerializerMethodField('_description')
     registered = serializers.SerializerMethodField('_registered')
@@ -192,10 +193,15 @@ class EventListSerializer(serializers.ModelSerializer):
 
     def _registered(self, instance):
         try:
-            return services.is_user_registered(self.context['request'].user,
-                                               instance)
+            registered = services.is_user_registered(
+                self.context['request'].user,
+                instance,
+            )
+            if registered is None:
+                return False
+            return registered
         except AttributeError:
-            return None
+            return False
 
     def _pizza(self, instance):
         pizza_events = PizzaEvent.objects.filter(event=instance)
diff --git a/website/events/models.py b/website/events/models.py
index 35d8fa263a2a527cf2f5407ff1575ca4c13e46f1..1181fc5f76872ab7febf1e163569249ffa8f38e0 100644
--- a/website/events/models.py
+++ b/website/events/models.py
@@ -224,13 +224,13 @@ class Event(models.Model, metaclass=ModelTranslateMeta):
     @property
     def registration_allowed(self):
         now = timezone.now()
-        return ((self.registration_start or self.registration_end) and
-                self.registration_end > now >= self.registration_start)
+        return (bool(self.registration_start or self.registration_end)
+                and self.registration_end > now >= self.registration_start)
 
     @property
     def cancellation_allowed(self):
         now = timezone.now()
-        return ((self.registration_start or self.registration_end)
+        return (bool(self.registration_start or self.registration_end)
                 and self.registration_start <= now < self.start)
 
     def is_pizza_event(self):