Ahh, information.
Okay, this definitely looks like a bug in the restful_authentication plugin. Look at the first comment here: http://agilewebdevelopment.com/plugins/restful_authentication
This seems to have been introduced lately, the last time I used restful_authentication it generated redirect_to :controller => '/session', :action => 'new'
I don't know if Rick has an official bug tracking site for his plugins (you'd think he'd be using Lighthouse <G>) so I've changed the subject in hopes he might be more likely to read this.