That depends a great deal on the personalities involved. There were few, if any, universally accepted and binding legal standards in feudal societies. Feudal laws and customs, therefore, tended to be local and personal.

I suppose it would technically depend on how high up you're talking. A king (which is 13th century France was actually starting to get pretty kingly) would be well informed as to what his vassals saw. He would see his peasantry in terms of Christendom. The subjects under his crown, or as statistics. Direct contact would be minimal.

However the further down the line you go the more contact you would have. Local counts and dukes were well aware of the on goings of their demesne and seeing as peasantry directly correlates to labor capability, they would be well aware as to the ongoings.

Now obviously this varies from person to person and place to place, but take for example the Cathar heresy that occurred between the 12th and 14th century. It was largely adopted by the lower vassals of the French crown, but only after making large waves within the community. Religion is formative and connecting in medieval history. Which is why I argue they would be perceived as Christendom, they are a collective of Christians, the one factor that doesn't change between social class, even if it was at times superficial.

So in this context contact could be argued as a deep theological connection, but a nearly deprived social connection. Class walls existed and defined society, only being broken by equally as powerful cultural barriers, such as the necessity to guide a labor force or control a group.