As to the restrictions on OSCE observers, these are military personnel with no need to be there. They are not from Boeing (airframe), General Electric (engines), etc.
Western media fingers are pointed at Russian involvement, but other sources provide conflicting information. For example, according to a Spanish air controller in Ukraine, the Kiev military authority informed the control tower of the downing at noon, approximately ten minutes after it disappeared from the radar screen. How could they have known without having concrete details on it being shot down?
Thomas Turk
Phuket