diff --git a/tabellio/contest/contest.py b/tabellio/contest/contest.py
index 6d1c856..1878dee 100644
--- a/tabellio/contest/contest.py
+++ b/tabellio/contest/contest.py
@@ -85,6 +85,15 @@ class Participate(BrowserView):
                 new_id = '%s-%s' % (new_id, counter)
                 break
 
+        for attr in ('name', 'address', 'zipcode', 'locality', 'phone',
+                     'email', 'answer1', 'answer2'):
+            if not self.request.form.get(attr, '').strip():
+                self.context.plone_utils.addPortalMessage(
+                        _(u'You must fill all fields to participate.'),
+                        type='warning')
+                self.request.response.redirect('./')
+                return
+
         type_info = portal_types.getTypeInfo('tabellio.contest.participant')
         type_info._constructInstance(self.context, new_id)
         object = self.context[new_id]
@@ -105,6 +114,11 @@ class PickWinner(BrowserView):
         if potential_winners:
             winner = random.SystemRandom().choice(potential_winners)
             winner.winner = True
+            self.context.plone_utils.addPortalMessage(
+                _(u'A winner has been picked.'))
+        else:
+            self.context.plone_utils.addPortalMessage(
+                            _(u'No winner could be found.'), type='error')
         self.request.response.redirect('./participants')