I wonder why only Benedikte is wearing the order and not her sisters? to me it looks a little odd for only one to be wearing an order but it must have been intentional otherwise i'm sure she could have taken it off.
Princess Benedikte was given the Dannebrogordenens Hæderstegn, which is not the Order of the Dannebrog itself. It is some kind of a cross of honour of the Order. Here are some pictures of the award: https://www.google.pl/search?q=Danne...w=1920&bih=919 Benedikte is Grand Commander (Storkommandor) of the Dannebrog, which is the highest , special class of the order, since 1993.
Congratulations to Princess Benedikte on turning 70. She looks young and fresh and should enjoy many more years in her role as Princess. I would imagine she might use the internet especially emails to keep in touch with her Charities and patronages.