WooCommerce Subscription product page with gifted subscriptions checkbox gets auto clicked upon page load.

auto-click gift woocommerce subscription

function auto_select_gift() {
  if ( is_single(56669) ) { //enter product id here
    ?>
    <script type="text/javascript">
      jQuery(document).ready(function ($) {
        document.getElementById("gifting_0_option").click(); // Click on the checkbox
      });
    </script>
  <?php
  }
}
add_action('wp_head', 'auto_select_gift');

The purpose of this is to make it painfully obvious on a certain product, that it is intended to be used for gifting, rather than buying for oneself.