diff --git a/src/Utils/Course.hs b/src/Utils/Course.hs
index 8d7e0062d..23a270169 100644
--- a/src/Utils/Course.hs
+++ b/src/Utils/Course.hs
@@ -42,20 +42,20 @@ mayEditCourse' muid ata (Entity cid Course{..}) =
 
 
 isSchoolAdmin :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value SchoolId) -> E.SqlExpr (E.Value Bool)
-isSchoolAdmin muid AuthTagActive{..} ssh = E.exists . E.from $ \(user `E.InnerJoin` userFunction) -> do
-  E.on $ user E.^. UserId E.==. userFunction E.^. UserFunctionUser
-  E.where_ $ E.just (user E.^. UserId)           E.==. E.val muid
-    E.&&. userFunction E.^. UserFunctionSchool   E.==. ssh
-    E.&&. userFunction E.^. UserFunctionFunction E.==. E.val SchoolAdmin
-    E.&&. E.val (authTagIsActive AuthAdmin)
+isSchoolAdmin muid AuthTagActive{..} ssh
+  | Just uid <- muid, authTagIsActive AuthAdmin = E.exists . E.from $ \(user `E.InnerJoin` userFunction) -> do
+    E.on $ user E.^. UserId E.==. userFunction E.^. UserFunctionUser
+    E.where_ $ user      E.^. UserId               E.==. E.val uid
+      E.&&. userFunction E.^. UserFunctionSchool   E.==. ssh
+      E.&&. userFunction E.^. UserFunctionFunction E.==. E.val SchoolAdmin
+  | otherwise = E.false
 
 isSchoolAdminLike :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value SchoolId) -> E.SqlExpr (E.Value Bool)
-isSchoolAdminLike muid ata@AuthTagActive{..} ssh = 
-        isSchoolAdmin muid ata ssh
-  E.||. (E.exists . E.from $ \(user `E.InnerJoin` userFunction) -> do
+isSchoolAdminLike muid ata@AuthTagActive{..} ssh
+  | Just uid <- muid = isSchoolAdmin muid ata ssh E.||. (E.exists . E.from $ \(user `E.InnerJoin` userFunction) -> do
     E.on $ user E.^. UserId E.==. userFunction E.^. UserFunctionUser
-    E.where_ $ E.just (user E.^. UserId) E.==. E.val muid
-      E.&&.   userFunction E.^. UserFunctionSchool E.==. ssh
+    E.where_ $ user         E.^. UserId               E.==. E.val uid
+      E.&&.    userFunction E.^. UserFunctionSchool   E.==. ssh
       E.&&. ( (userFunction E.^. UserFunctionFunction E.==. E.val SchoolEvaluation
           E.&&. E.val (authTagIsActive AuthEvaluation))
         E.||. (userFunction E.^. UserFunctionFunction E.==. E.val SchoolExamOffice
@@ -64,50 +64,58 @@ isSchoolAdminLike muid ata@AuthTagActive{..} ssh =
           E.&&. E.val (authTagIsActive AuthAllocationAdmin))
       )
     )
+  | otherwise = E.false
 
 isCourseLecturer :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> E.SqlExpr (E.Value Bool)
-isCourseLecturer muid AuthTagActive{..} cid = E.exists . E.from $ \(user `E.InnerJoin` lecturer) -> do
-  E.on $ user E.^. UserId E.==. lecturer E.^. LecturerUser
-  E.where_ $ E.just (user E.^. UserId) E.==. E.val muid
-    E.&&. lecturer E.^. LecturerCourse E.==. cid
-    E.&&. E.val (authTagIsActive AuthLecturer)
+isCourseLecturer muid AuthTagActive{..} cid
+  | Just uid <- muid, authTagIsActive AuthLecturer = E.exists . E.from $ \(user `E.InnerJoin` lecturer) -> do
+    E.on $     user  E.^. UserId         E.==. lecturer E.^. LecturerUser
+    E.where_ $ user  E.^. UserId         E.==. E.val uid
+      E.&&. lecturer E.^. LecturerCourse E.==. cid
+  | otherwise = E.false
 
 isCourseTutor :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> E.SqlExpr (E.Value Bool)
-isCourseTutor muid AuthTagActive{..} cid = E.exists . E.from $ \(tutor `E.InnerJoin` tutorial) -> do
-  E.on $ tutor E.^. TutorTutorial E.==. tutorial E.^. TutorialId
-  E.where_ $ E.just (tutor E.^. TutorUser) E.==. E.val muid
-    E.&&. tutorial E.^. TutorialCourse E.==. cid
-    E.&&. E.val (authTagIsActive AuthTutor)
+isCourseTutor muid AuthTagActive{..} cid
+  | Just uid <- muid, authTagIsActive AuthTutor = E.exists . E.from $ \(tutor `E.InnerJoin` tutorial) -> do
+    E.on $     tutor E.^. TutorTutorial  E.==. tutorial E.^. TutorialId
+    E.where_ $ tutor E.^. TutorUser      E.==. E.val uid
+      E.&&. tutorial E.^. TutorialCourse E.==. cid
+  | otherwise = E.false
 
 isCourseSheetCorrector :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> E.SqlExpr (E.Value Bool)
-isCourseSheetCorrector muid AuthTagActive{..} cid = E.exists . E.from $ \(sheetCorrector `E.InnerJoin` sheet) -> do
-  E.on $ sheetCorrector E.^. SheetCorrectorSheet E.==. sheet E.^. SheetId
-  E.where_ $ E.just (sheetCorrector E.^. SheetCorrectorUser) E.==. E.val muid
-    E.&&. sheet E.^. SheetCourse E.==. cid
-    E.&&. E.val (authTagIsActive AuthCorrector)
+isCourseSheetCorrector muid AuthTagActive{..} cid
+  | Just uid <- muid, authTagIsActive AuthCorrector = E.exists . E.from $ \(sheetCorrector `E.InnerJoin` sheet) -> do
+    E.on $     sheetCorrector E.^. SheetCorrectorSheet E.==. sheet E.^. SheetId
+    E.where_ $ sheetCorrector E.^. SheetCorrectorUser  E.==. E.val uid
+      E.&&.    sheet          E.^. SheetCourse         E.==. cid
+  | otherwise = E.false
 
 isCourseExamCorrector :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> E.SqlExpr (E.Value Bool)
-isCourseExamCorrector muid AuthTagActive{..} cid = E.exists . E.from $ \(examCorrector `E.InnerJoin` exam) -> do
-  E.on $ examCorrector E.^. ExamCorrectorExam E.==. exam E.^. ExamId
-  E.where_ $ E.just (examCorrector E.^. ExamCorrectorUser) E.==. E.val muid
-    E.&&. exam E.^. ExamCourse E.==. cid
-    E.&&. E.val (authTagIsActive AuthExamCorrector)
+isCourseExamCorrector muid AuthTagActive{..} cid
+  | Just uid <- muid, authTagIsActive AuthExamCorrector = E.exists . E.from $ \(examCorrector `E.InnerJoin` exam) -> do
+    E.on $     examCorrector E.^. ExamCorrectorExam E.==. exam E.^. ExamId
+    E.where_ $ examCorrector E.^. ExamCorrectorUser E.==. E.val uid
+      E.&&.    exam          E.^. ExamCourse        E.==. cid
+  | otherwise = E.false
 
 isCourseParticipant :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> E.SqlExpr (E.Value Bool)
-isCourseParticipant muid AuthTagActive{..} cid = E.exists . E.from $ \courseParticipant -> E.where_ $ 
-        E.just (courseParticipant E.^. CourseParticipantUser) E.==. E.val muid
-  E.&&. courseParticipant E.^. CourseParticipantCourse E.==. cid
-  E.&&. courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
-  E.&&. E.val (authTagIsActive AuthCourseRegistered)
+isCourseParticipant muid AuthTagActive{..} cid
+  | Just uid <- muid, authTagIsActive AuthCourseRegistered = E.exists . E.from $ \courseParticipant -> E.where_ $ 
+          courseParticipant E.^. CourseParticipantUser   E.==. E.val uid
+    E.&&. courseParticipant E.^. CourseParticipantCourse E.==. cid
+    E.&&. courseParticipant E.^. CourseParticipantState  E.==. E.val CourseParticipantActive
+    E.&&. E.val (authTagIsActive AuthCourseRegistered)
+  | otherwise = E.false
 
 isCourseApplicant :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> Maybe (E.SqlExpr (E.Value AllocationId)) -> E.SqlExpr (E.Value Bool)
-isCourseApplicant muid AuthTagActive{..} cid maid = E.exists . E.from $ \courseApplication -> E.where_ $
-        E.just (courseApplication E.^. CourseApplicationUser) E.==. E.val muid
-  E.&&. courseApplication E.^. CourseApplicationCourse E.==. cid
-  E.&&. E.val (authTagIsActive AuthApplicant)
-  E.&&. maybe E.true
-          (\aid -> E.just aid E.==. courseApplication E.^. CourseApplicationAllocation)
-          maid
+isCourseApplicant muid AuthTagActive{..} cid maid
+  | Just uid <- muid, authTagIsActive AuthApplicant = E.exists . E.from $ \courseApplication -> E.where_ $
+          courseApplication E.^. CourseApplicationUser   E.==. E.val uid
+    E.&&. courseApplication E.^. CourseApplicationCourse E.==. cid
+    E.&&. maybe E.true
+            (\aid -> E.just aid E.==. courseApplication E.^. CourseApplicationAllocation)
+            maid
+  | otherwise = E.false
 
 isCourseAssociated :: Maybe UserId -> AuthTagActive -> E.SqlExpr (E.Value CourseId) -> Maybe (E.SqlExpr (E.Value AllocationId)) -> E.SqlExpr (E.Value Bool)
 isCourseAssociated muid ata cid maid =