diff --git a/src/Controller/Teamer/Application/CreateController.php b/src/Controller/Teamer/Application/CreateController.php
index 6070167..ab82d55 100644
--- a/src/Controller/Teamer/Application/CreateController.php
+++ b/src/Controller/Teamer/Application/CreateController.php
@@ -31,6 +31,27 @@ class CreateController extends AbstractController
         /** @var User $user */
         $user = $this->getUser();
         $teamer = $user->getTeamer();
+
+        // Only allow applications on empty slots
+        $availableSlots = (int) $assignment->getAvailableDispositions();
+        if (0 < $availableSlots) {
+            $this->addFlash('error', 'Auf diesem Einsatz sind bereits alle Plätze belegt');
+
+            return $this->redirectToRoute('app_teamer_index');
+        }
+
+        // Only teamers without existing applications may apply to the assignment
+        $existingApplication = $this
+            ->entityManager
+            ->getRepository(Application::class)
+            ->findOneBy(['teamer' => $teamer, 'assignment' => $assignment]);
+
+        if (null !== $existingApplication) {
+            $this->addFlash('error', 'Du hast dich bereits auf diesen Einsatz beworben');
+
+            return $this->redirectToRoute('app_teamer_index');
+        }
+
         $application = new Application($assignment, $teamer);
 
         $form = $this->createForm(TeamerApplicationType::class, $application);
diff --git a/src/Security/Voter/AssignmentVoter.php b/src/Security/Voter/AssignmentVoter.php
index 6395513..fa14f8e 100644
--- a/src/Security/Voter/AssignmentVoter.php
+++ b/src/Security/Voter/AssignmentVoter.php
@@ -2,10 +2,7 @@
 
 namespace App\Security\Voter;
 
-use App\Entity\Application;
 use App\Entity\Assignment;
-use App\Entity\User;
-use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Bundle\SecurityBundle\Security;
 use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
 use Symfony\Component\Security\Core\Authorization\Voter\Voter;
@@ -18,10 +15,8 @@ class AssignmentVoter extends Voter
     public const PUBLISH = 'PUBLISH';
     public const CALL_OFF = 'CALL_OFF';
 
-    public function __construct(
-        private readonly Security $security,
-        private readonly EntityManagerInterface $entityManager,
-    ) {
+    public function __construct(private readonly Security $security)
+    {
     }
 
     protected function supports(string $attribute, mixed $subject): bool
@@ -30,65 +25,31 @@ class AssignmentVoter extends Voter
             return false;
         }
 
-        return in_array($attribute, [static::VIEW, static::EDIT, static::APPLY, static::PUBLISH, static::CALL_OFF]);
+        return in_array($attribute, [self::VIEW, self::EDIT, self::APPLY, self::PUBLISH, self::CALL_OFF], true);
     }
 
     protected function voteOnAttribute(string $attribute, mixed $subject, TokenInterface $token): bool
     {
-        /** @var Assignment $assignment */
-        $assignment = $subject;
-
-        // All authenticated users may view assignments
-        if (static::VIEW === $attribute && null !== $token->getUser()) {
-            return true;
-        }
-
-        // Only users with administrative role may edit assignments
-        if (static::EDIT === $attribute) {
-            return $this->security->isGranted('ROLE_ADMINISTRATIVE');
-        }
-
-        // Only users with administrative role may publish assignments currently in draft
-        if (static::PUBLISH === $attribute) {
-            return Assignment::STATUS_DRAFT === $assignment->getStatus()
-                && $this->security->isGranted('ROLE_ADMINISTRATIVE');
-        }
-
-        // Only users with administrative role may call off assignments
-        if (static::CALL_OFF === $attribute) {
-            return Assignment::STATUS_CALLED_OFF !== $assignment->getStatus()
-                && $this->security->isGranted('ROLE_ADMINISTRATIVE');
-        }
-
-        // Only allow applications to published, not deleted and not called off assignments
-        if (
-            true === in_array($assignment->getStatus(), [
-                Assignment::STATUS_DRAFT,
-                Assignment::STATUS_DELETED,
-                Assignment::STATUS_CALLED_OFF,
-            ])) {
+        if (null === $token->getUser()) {
             return false;
         }
 
-        // Only allow applications on empty slots
-        $availableSlots = (int) $assignment->getAvailableDispositions();
-        if (0 < $availableSlots) {
-            return $assignment->getDispositions()->count() < $availableSlots;
-        }
+        /** @var Assignment $assignment */
+        $assignment = $subject;
 
-        // Only teamers without existing applications may apply to the assignment
-        if ($this->security->isGranted('ROLE_TEAMER')) {
-            /** @var User $user */
-            $user = $token->getUser();
-            $teamer = $user->getTeamer();
-            $application = $this
-                ->entityManager
-                ->getRepository(Application::class)
-                ->findOneBy(['teamer' => $teamer, 'assignment' => $assignment]);
-
-            return null === $application;
-        }
-
-        return false;
+        return match ($attribute) {
+            self::VIEW => true,
+            self::EDIT => $this->security->isGranted('ROLE_ADMINISTRATIVE'),
+            self::PUBLISH => Assignment::STATUS_DRAFT === $assignment->getStatus()
+                && $this->security->isGranted('ROLE_ADMINISTRATIVE'),
+            self::CALL_OFF => Assignment::STATUS_CALLED_OFF !== $assignment->getStatus()
+                && $this->security->isGranted('ROLE_ADMINISTRATIVE'),
+            self::APPLY => false === in_array($assignment->getStatus(), [
+                Assignment::STATUS_DRAFT,
+                Assignment::STATUS_DELETED,
+                Assignment::STATUS_CALLED_OFF,
+            ], true),
+            default => false,
+        };
     }
 }