FIX: Move check to right serializer.

app/serializers/basic_user_serializer.rb

@@ -1,10 +1,6 @@
 class BasicUserSerializer < ApplicationSerializer
   attributes :id, :username, :avatar_template
 
-  def include_name?
-    SiteSetting.enable_names?
-  end
-
   def avatar_template
     if Hash === object
       User.avatar_template(user[:username], user[:uploaded_avatar_id])

app/serializers/group_post_user_serializer.rb

@@ -1,3 +1,7 @@
 class GroupPostUserSerializer < BasicUserSerializer
   attributes :title, :name
+
+  def include_name?
+    SiteSetting.enable_names?
+  end
 end