What is the point to play a game if you can decide what is going on for the next 100 turns? Seriously?
Well thats the hole point about diplomacy know I know the AI will backstabb me and declare on me when I have a lower military not much of a suprise more predictable...
And every AI does this not just certain types...
Not really a good game design...
The probabilities are higher, but it's not impossible to see no backstab at all. It's in fact pretty complicated right now to make good decision and not be attacked. Only a few players have done that. The diplo system is much complicated and adaptation is harder. If a weaker civ attacks you, get their cities and make gold by selling them or puppeting them. For sure you have high chances to be backstabbed if you stay low in military. At least the AI acts like it should in that case. Be a man and stay strong

Like LeRoiSoleil said, in mankind history, no leaders would have let their civ with no military, sit down and pray to not be attacked. Finally we have something more realistic.
AIs are your ennemies, not your friends.