Show WooCommerce Store Notice to Logged In Previous Customers Only.

modify_woocommerce_demo_store_customers_only.php

<?php
/**
 * Show WooCommerce Store Notice to Logged In Previous Customers Only.
 */
function modify_woocommerce_demo_store_customers_only( $notice_html ) {
	if ( ! is_user_logged_in() ) {
		return '';
	}

	// Get the user object.
	$user = get_userdata( get_current_user_id() );

	// Get all the user roles as an array.
	$user_roles = $user->roles;

	// Check if the role you're interested in is present in the array.
	if ( ! in_array( 'customer', $user_roles, true ) ) {
		$notice_html = '';
	}

	return $notice_html;
}
add_filter( 'woocommerce_demo_store', 'modify_woocommerce_demo_store_customers_only', 11 );