Every hotel isn't going to be perfect for every traveler (or group of travelers). Given the currency used, this hotel isn't in the United States. While rooms that accommodate 2 adults and 2 children are the default in the US, that's not true in other parts of the world.

What happens when you search for 2 adults and 1 child. If you don't see extra charges, that means their standard room only allows three people. Or better yet, pick up the phone and call the hotel or Radisson Central Reservations. People at either place will be able to explain if why the extra charges are being added.