For me, the biggest tragedy that after the shoot down of AN-26 the Civil Aviation authority in Ukraine and Euro zone only give (in my opinion) limited warning. The shoot down of that AN-26 shoud ring the bell on civil aviation risk assesment that the rebel have 'potential' more SAM capabilities that just simple Manpads and SHORAD, and they are 'willing' too used it on every airborne target above their heads.
With no air fighter on their own, they will simply put conclusion on their mind, that whatever fly above their heads is enemy combatan. This attitude will be the same whether that para military/separatist group is either HAMAS, ISIS, or any separatist rebels group in the world. It's happen differently simply because the Ukraine's one can get their hand on much longer range SAM systems that SHORAD.
Risk assesment should put this conditions on hand; the historical capabilities of Ukraine's separatist getting their hand on Ukraine's military hardware before, the availability of Ukraine's long range SAM in the area (thus potential being taken over by the rebels), and again most importantly in my mind is their willingness to shoot down anything above their heads, as AN-26 incidents already shown.
As comparisons; when a volcanic eruption happen, the civil aviations ussual practises then will put allert to every airliners to avoid the area in 'any' hight simply due to unpredictable eruption ash cloud movement. This Ukraine conflict should be treated the same simply due to 'unpredictable' behaviors of the combatan Plus availability means to shoot down anything above their heads.
Risk Management assesment should see that. It's tragically happen (as in many situations in the world), Risk assesment sometimes comes late to realisation.