One important and major advantage of advance reservations is that the visitor will be met at the airport straight away by a representative of the houseboat-owner it's not easy for newcomers to find their way among the boats.
Another advantage of advance reservations is that the visitors will be invited to a free lunch at the owner's houseboat. 
mnli hypothesis: Another advantage of advance reservations is that the visitors will be invited to a free lunch at the owner's houseboat.  premise: One important and major advantage of advance reservations is that the visitor will be met at the airport straight away by a representative of the houseboat-owner it's not easy for newcomers to find their way among the boats.