WPMU A+ use default name and email when profile meta field is empty and booking created by the admin

code.php

<?php

add_filter( 'app-appointment-inline_edit-save_data', 'app_inline_save_cb' );
function app_inline_save_cb( $data ){
	$user = get_userdata( $data['user'] );
	if ( username_exists( $user->user_login ) ){
		$data['email'] = $data['email'] == '' ? $user->user_email : $data['email'];
		$data['name'] = $data['name'] == '' ? $user->display_name : $data['name'];
	}
	return $data;
}