やらかしました。「配送先がご購入者と異なっているのに、ご購入者へ向けて発送」です。

そこで、対策としてこのコードを追加しました。ご注文の管理画面で注意喚起するコードです。

add_action( 'woocommerce_admin_order_data_after_order_details', 'my_addresscheck');
function my_addresscheck( $order ){ 
	
	$billing_first_name =　$order->billing_first_name;
	$billing_last_name = $order->billing_last_name;
	$billing_company = $order->billing_company;
	$billing_address_1 = $order->billing_address_1;
	$billing_address_2 = $order->billing_address_2;
	$billing_city = $order->billing_city;
	$billing_state = $order->billing_state;
	$billing_postcode = $order->billing_postcode;
	
	$shipping_first_name =　$order->shipping_first_name;
	$shipping_last_name = $order->shipping_last_name;
	$shipping_company = $order->shipping_company;
	$shipping_address_1 = $order->shipping_address_1;
	$shipping_address_2 = $order->shipping_address_2;
	$shipping_city = $order->shipping_city;
	$shipping_state = $order->shipping_state;
	$shipping_postcode = $order->shipping_postcode;
		
	
	if ( 
	strcmp($billing_postcode ,$shipping_postcode ) ||
	strcmp($billing_first_name,$shipping_first_name)  || 
	strcmp($billing_last_name , $shipping_last_name ) ||
	strcmp($billing_company , $shipping_company ) ||
	strcmp($billing_address_1  ,$shipping_address_1  ) ||
	strcmp($billing_address_2  ,$shipping_address_2 ) ||
	strcmp($billing_city  ,$shipping_city ) ||
	strcmp($billing_state  ,$shipping_state )  
	) 
		{
?>
<p style="color: red;">■■■■■■注意！ 購入者とお届け先が異なっています■■■■■■</p>
<?php


	}
}