warn users with trading lists but no neomail address

app/views/closet_hangers/index.html.haml

@@ -75,6 +75,8 @@
                   = closet_visibility_descriptions
               - if has_lists?(owned)
                 %h4= t '.unlisted.header'
+            - if !@public_perspective
+              = render partial: 'closet_lists/trading_neomail_warning', locals: {list: @user.null_closet_list(owned), user: @user}
             .closet-list-content
               .closet-list-hangers
                 = render_unlisted_closet_hangers(owned)

app/views/closet_lists/_closet_list.html.haml

@@ -11,6 +11,9 @@
           = submit_tag t('.delete'), :confirm => closet_list_delete_confirmation(closet_list)
     %h4= closet_list.name
 
+  - if show_controls
+    = render partial: 'closet_lists/trading_neomail_warning', locals: {list: closet_list, user: @user}
+
   .closet-list-content
     - if closet_list.description?
       = closet_list_description_format closet_list

app/views/closet_lists/_trading_neomail_warning.html.haml

@@ -0,0 +1,2 @@
+- if list.visibility_level.trading? && !user.contact_neopets_username?
+  %p.warning= t 'closet_lists.closet_list.trading_neomail_warning_html'

config/locales/en.yml

@@ -185,6 +185,12 @@ en:
           Are you sure you want to delete "%{list_name}"? Even if you do, we'll
           remember that you want these items.
       empty: This list is empty.
+      trading_neomail_warning_html:
+        You've marked this list as Trading, so folks will discover it via Dress
+        to Impress, but they might not know how to contact you. If you'd like
+        to hear from those people, <strong>set a Neomail address at the top of
+        the page</strong>.
+        (If not, maybe you want a Public list instead of Trading.)
       
     edit:
       title: Editing list "%{list_name}"