With mrbs 1.4 it was possible to see bookings without login. mrbs 1.10 requires a login to display a booking
Change line 26 of mrbs_auth.inc from
$page_level['view_entry.php'] = 1;
to
$page_level['view_entry.php'] = ($auth['deny_public_access']) ? 1 : 0;
Change line 26 of mrbs_auth.inc from
to