So UkSATSE (Ukrainian State Air Traffic Services Enterprise) deliberately leaving airspace over a war zone available to CAT has no bearing...
Little . They claimed that based on the information they had the rebels had no access to no high altitude missiles.( which might be true ) UkSATSE also needed the cash of the overflights charges to continue operating. so no real incentive to go beyond what their own State intelligence told them .
But some airlines did deliberately avoid that airspace based on their State info.
Was this just precautionary of based on real intelligence? I leave the answer open as I do not have it. What is sure is that they did not share that info with other airlines, not even within their own Airline alliance.. ICAO since jumped in , and there is now a policy/procedures for such cases. Too late unfortunately for MH17 .