The zero dollar tours bring almost no tax revenue for the Thai state nor any relevant sales for the domestic Thai tourism businesses. The trips are booked in China and fully paid there. Hotel rooms, restaurant visits, bus transfers and shopping stops are only booked in Chinese-controlled companies. From an accounting perspective, it is now possible for the service invoices from Chinese-controlled companies to only be issued in the amount of the actual costs, so that no taxable profits arise within Thailand. The profits then remain entirely in China. With this type of mass tourism, Thailand only loses because the infrastructure has to be paid for and a lot of nature get destroyed.
The Thai Tourism Authority must learn that simply increasing the number of visitors does not necessarily lead to higher revenues if all the direct and indirect costs to the Thai ecosystem are taken into account.