HTML_Template_Flexy private vars in controller

Is Flexy skipping private vars in the controller and doesn't output them ? I mean vars that begins by an underscore. So if $_test in the controller and {_test} in the template, {_test} is outputed without modification ({test} from $test is outputed normally). I would like to know if this is an intended feature and if this feature will remains in future versions of flexy. It is (would be ?) a nice feature, when setting vars to output automatically (with get_object_vars($this) e.g.), also providing a mean to set a nice api / doc for designers (hiding private vars). Regards, Didier