When no other traffic exists I have observed that cars seldom ever completely stop also. My commute to the train includes a heavy bike and backpack, -- and I'm looking to not get sweaty. So I ride at a very leisurely pace (in the morning). It's just over two miles through residential areas with lot of stop signs. Cars approaching a stop sign with me will slow to about my speed and then accelerate through. It sort of appears they have stopped but all they really did was slow to my speed. This helps me to justify not fully stopping (or even slowing down significantly) at absent stop signs.