WooCommerce: modify WooCommerce default customer role

functions.php

<?php // Do not include this if already open! Code goes in theme functions.php.
/**
 * woocommerce_custom_new_customer_data
 *
 * @access      public
 * @since       1.0 
 * @return      void
*/
function woocommerce_custom_new_customer_data( $new_customer_data ) {
	
	$new_customer_data['role'] = 'subscriber';
	
	return $new_customer_data;
	
}
add_filter( 'woocommerce_new_customer_data', 'woocommerce_custom_new_customer_data');