Named routes generated without a method

This output is from rake routes (not all the routes for cart_items are included)

home               /              {:method=>:get, :action=>"index", :controller=>"home"}

cart_items GET     /cart_items    {:action=>"index", :controller=>"cart_items"}

Notice how the first route does not have a method.

Here is the code from routes.rb

map.home '/', :controller => 'home', :action => 'index'

map.resources :cart_items

Since moving to Rails 2.1 this has been causing intermittent errors

ActionController::MethodNotAllowed Only get, head, post, put, and delete requests are allowed.

Googling suggests these errors might be due to Mongrel. But whether its Mongrel or Rails 2.1 or something else, it seems to me that fixing the underlying routes so that a specific GET method is generated by default would be a good thing to do.