Since the flash gets converted to a cookie in an after_filter any flash messages created in a before_filter will not get converted.

before_filter :find_article
def find_article
  @article = Article.find(params[:id]) if params[:id]
  unless @article
    flash[:notice] = "Could not find Article"
    redirect_to :action => "index"
  end
end

Possible solution, convert to a before filter? Leave as is, just make a note in the docs?