Rails - When to escape ampersands in query string

In the following situations which is correct?

class SomeController
  def action
    yada yada
    value = CGI.escape(value)
    value2 = CGI.escape(value2)
    redirect_to "http://ift.tt/1PE8y5B}"
    redirect_to "http://ift.tt/1MzA1ea}"
  end
end

Or in the view,

link_to "http://ift.tt/1PE8wuF"
link_to "http://ift.tt/1PE8wuF"