I've had pedal strike a couple of time, going over high speed bumps and cornering on a reverse camber. It has never toppled me although it has come close. It usually happens when there is too much stuff happening to remember to raise my cranks, perhaps a pedestrian crossing the road plus a car coming up to fast.
Did you have toe clips/clipless? If not, did the strike dislodge your feet from the platforms? Does your bike have aparticularly low BB/long cranks?