One thing I noted from the beginning of the thread, which I think is ruled out.
Someone mentioned the ISIS would try to shoot down a Russian jet, with the argument Russia is now involved in Syria. Some then mentioned that would be unlikely, since ISIS would be unable to see who they were shooting at.
Are anyone aware that wrongdoers could very well be using the same tool we use everyday in following flights? Give the FlightRadar24 or another equivalent, and they'll have all the information they need to identify overflights.
Giving the generel public acces to data, previously keept for ATC, could very well be creating a sideeffect of not being able to "protect" flights.....
Sorry for the detour, but think about it, now back to the sad accident.