So GUWonder, what you are saying is essentially this...:

If someone is granted a multi-entry Schengen visa for a year... then any trips they make during that year have to involve the country that originally issued the visa?

If that's really how some countries are interpreting the rules then I think there is something wrong, and someone should perhaps mount a challenge against this interpretation! I thought the whole point of Schengen was that one has one visa to cover the lot, and the point of a multi-entry visa was that one can come and go freely, in the entire area, during the period of validity.