Should traditional moule marinier have cream in it? I'm about to make moule marinier and was surprised to see a lot of the recipes had cream in them.  I'm sure I remember watching an episode of Celebrity Masterchef where they had to prepare moule marinier and the judges being surprised at the people who put cream in the dish.

As it is supposedly a sailors dish, and I can't imagine sailors having fresh cream to hand it seems unlikely that they would traditionally contain cream.  Is this right?  Should moule marinier have cream in it?  Or should I just finish the cooking liquor with a knob of butter at the end?
Traditional Moules a la mariniere is finished by reducing the cooking liquid until it is concentrated and then "mounting" it with butter (monter au beurre).

Mouclade is a traditional mussel preparation from the region of Bordeaux where the cooking liquid is enriched at the end with heavy cream and sometimes egg yolks, thus the reason the judges on your show were commenting that the cream was incorrect.