In the Www::Mechanize documents, you see that redirect_ok() is an over loaded method of LWP::UserAgent. If you look LWP::UserAgent docs you will find the following
$ua->redirect_ok( $prospective_request, $response )
This method is called by request() before it tries to follow a red
+irection to the request in $response. This should return a TRUE value
+ if this redirection is permissible. The $prospective_request will be
+ the request to be sent if this method returns TRUE.
The base implementation will return FALSE unless the method is in
+the object's requests_redirectable list, FALSE if the proposed redire
+ction is to a "file://..." URL, and TRUE otherwise.
Hope this helps!