O padrão foi desativado quando foi introduzido, no bash 2.02:
@@ -119,6 +123,10 @@ int interactive = 0;
/* Non-zero means that the shell was started as an interactive shell. */
int interactive_shell = 0;
+/* Non-zero means to send a SIGHUP to all jobs when an interactive login
+ shell exits. */
+int hup_on_exit = 0;
+