There have been many misunderstandings in history that has caused or come close to causing a war. It has happened many times during the Cold War where, due to glitches in the missile system or other types of events nuclear missiles have been activated and the other side, seeing it as a threat have activated their own weapons.
For some reason as our race has grown and learned, we have left behind a lot of our simple, yet important teachings. Not everyone is dangerous, or out to do harm. Granted there are those people who do such, but many battles have taken place simply because of a misunderstanding and lack of communication.
In 2013, planets were mistaken for "Chinese spy drones" by the Indian army. This is not the only mistake that has caused political tension: the Swiss army once accidentally wandered into Lichtenstein. When countries misunderstand each other, their first instinct is to fight back, simply based on a few silly mistakes.
At this point, almost everybody knows how important communication is to relationships of any kind. This is especially true between global superpowers, and in a scenario such as this one, could avoid significant conflicts. I would argue that China should have communicated its intentions to India before violating its air space, to avoid any potential problems, such as India assuming that China was spying on them, which could have resulted in them shooting down what they thought were spy drones. A simple miscommunication could have led to an unnecessary war.