Why is it mandatory for me to indicate the Nationality of the guests?

Why is it mandatory for me to indicate the Nationality of the guests?

Local Market Rates

Not all of the hotel rates displayed on the Travelgo website are applicable for the local market. In addition, some other markets may be affected and in such cases the hotel is within their rights to change the rates without prior notice.
You agree that Passenger nationality declaration is mandatory and must be determined by selecting “Client Nationality” at the time of booking. This information must be in accordance with the Passenger passport. False declaration of Passenger nationality may cause consequences for which We cannot be held liable. If You do not change Client Nationality, Agency nationality (Irish or British) will be taken as Passenger nationality by default. In case, any financial damage occurs due to false nationality declaration, by the Travelgo It cannot be held liable and no liability for damages arises.