The passengers of flight MH17 thought that they would be safe in the air. They knew that the authorities go to extraordinary lengths to ensure their safety, especially from terrorism. No doubt every passenger went through the security at the airport, pulling out their laptops, tablets and smart phones, carefully placing their liquids in an appropriate sized clear plastic bag, and walking without shoes and boots through the scanners at the airport. Some were frisked, carefully. perhaps some had a small pair of nail scissors or tweezers confiscated and their hold luggage was screened with modern technology; some of it may have been opened for random inspection or to check something that may have looked wrong on the computer screen as it went through.
So with all this security I wonder why the airline chose to fly of a part of the world where people were fighting with modern weapons. Presumably they chose to do this not because there were no other routes available but to save fuel and thus save money. The authorities as well as the airline knew that the route would take them over an war zone. In war zones and above war zones accidents happen and danger lurks. Nevertheless the route was approved and away went the plane stuffed full of people who went (or were forced) to go to great lengths in the name of safety.
It is an odd world.