Hazard warning lights

Earlier this week when I was driving home from work I had to brake a bit harder than normal in front of an intersection. I wouldn't call it an emergency stop, I have braked harder on previous occasions. But this time the car suddenly indicated that the hazard warning light were on. I am 100 per cent certain that I didn't switch them on by accident. The button is located on the top right of the dashboard by the air vents, far from the steering wheel. But here I was standing on the road and the car was telling me that my warning lights were flashing. I didn't quite believe it and so I pulled over and got out of the car to look. The lights were flashing alright. I got back in and turned them off with the button.

When I got home I checked the manual and it said that the lights will flash if the airbag has been triggered off. But I had just used the brakes a bit harder than normal. My airbags were still safe and sound.

So what had happened? Was it just an electronic glitch?

Btw, this wasn't a big deal, just a bit strange. I'm still very happy with my Saab :)