Woo Checkout Spam

functions.php

function wcs_checkout_field( $checkout ) {
 woocommerce_form_field(
  'wcs_buyer_gift',
   array(
    'type'          => 'text',
    'class'         => array('wcs-field form-row-wide'),
   ),
  $checkout->get_value( 'wcs_buyer_gift' )
 );
}
add_action( 'woocommerce_after_order_notes', 'wcs_checkout_field' );

function wcs_checkout_field_process() {
 if ( !empty( $_POST['wcs_buyer_gift'] ) ) {
  wc_add_notice( __( 'Unable to submit order, please contact our support.' ), 'error' );
 }
}
add_action('woocommerce_checkout_process', 'wcs_checkout_field_process');

function wcs_header_css() {
 echo '<style>.wcs-field {display:none;}</style>';
}
add_filter('wp_head', 'wcs_header_css', 9999 );