gistfile1.txt

<%= form_tag ... do %>
  <span>something</span>
  <%= not_html_safe %>
<% end %>


That ends up making the entire block inside the form_tag do html escaped, which ordinarily isn't what happens in a view, but since it's inside a 'do' block, it does.

...which is why it's important for helper methods that return html to .html_safe it BEFORE they return it, like Rails own helpers do.