Deprecation problem with Errors#invalid?(attribute)

Unable to reproduce on edge Rails:

$ script/rails g controller territories new 
...
$ script/rails g model territory 
...
$ rake db:migrate
...

app/views/territories/new.html.erb:

<%= form_for @territory do |f| %>
  <%= f.label :id %>
  <%= f.text_field :id %>
<% end %>

app/controllers/territories_controller.rb

class TerritoriesController < ApplicationController
  def new
    @territory = Territory.new
  end
end

routes.rb:

Ticket5745::Application.routes.draw do
  resources :territories
end

A request to http://localhost:3000/territories/new renders correctly with no error messages:

$ script/rails s
=> Booting WEBrick
=> Rails 3.1.0.beta application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2010-10-09 17:06:23] INFO  WEBrick 1.3.1
[2010-10-09 17:06:23] INFO  ruby 1.9.2 (2010-08-18) [x86_64-darwin10.4.0]
[2010-10-09 17:06:23] INFO  WEBrick::HTTPServer#start: pid=14814 port=3000


Started GET "/territories/new" for 127.0.0.1 at 2010-10-09 17:07:22 +0200
  Processing by TerritoriesController#new as HTML
Rendered territories/new.html.erb within layouts/application (7.2ms)
Completed 200 OK in 19ms (Views: 10.4ms | ActiveRecord: 0.0ms)

Besides: Making the id column a user input is, mildly speaking, an extremely bad idea, and you should expect to encounter problems.