WP Protect user account from deletion

gistfile1.aw

add_action( 'delete_user', 'dont_delete_user' );
function dont_delete_user( $id ) {
    $dont_delete_ids = array( 1, 2, 3, 4 ); // protected user IDs

    if ( in_array( $id, $dont_delete_ids ) )
        wp_die( 'You cannot delete this user account.' );
}