Originally Posted by
WideScreen
Yes and no.
IF it had been known to Ukraine, that the airspace above the FL250 (or so, bear me the exact FL) was unsafe, the airspace would have been closed. Though according to available information, there were no weapons able to reach that Height/Altitude/FL (choose what measuring method you want to use) in that area, so the upper transit airways were presumed to be safe.
The original restriction was to Fl 250, it was then (prior to the shoot down) lifted to Fl 320.