Default shipping option

Hi,

Is there a way to disable the default shipping option, forcing the customer to make a selection before being able to complete checkout?

I found the below script that does do this, but once the user makes a selection, that selection is kept for the session.

// To test this code, open a private/incognito window, add an item to the cart and then go to cart page.
// Once an option is choosen, it will be the default option from that moment onwards.

// Code to clear default shipping option.
add_filter( 'woocommerce_shipping_chosen_method', '__return_false', 99);

// Code to clear default payment option.
add_filter( 'pre_option_woocommerce_default_gateway' . '__return_false', 99 );