So one of my new personal websites sells virtual products where customers buy just one product at a time. I don’t need quantities and nor do I want quantity boxes on the product page or the checkout, there just no need for it. So there could be a way to bring in some jQuery into the WordPress admin to force the check box on the product edit page but a neater solution is to actually just drop this into the functions.php file or seperate plugin file to achieve the same thing:
function default_no_quantities( $individually, $product ){
$individually = true;
return $individually;
}
add_filter( 'woocommerce_is_sold_individually', 'default_no_quantities', 10, 2 );
Now, when you create a new product, you will notice the checkbox is NOT checked, however if you publish the product with it unchecked, there will be no quantity allocated to the product.