Hello/Hola also claims they are staying with WA and Máxima.
he Spanish royal family is holidaying at the Dutch royal family's mansion in the Peloponnese region of Greece, according to reports
www.hellomagazine.com
Or better said: they say “ it is believed that…” but they fail to mention by whom it is believed and why we should believe those beliefs. Other than suggesting that the two couples are close, another assumption they fail to explain.
As said, they will have relatives and family friends in the area and they have more than enough means to rent a place of their own, so there are many possibilities other than WA and Máxima’s house.