I suspect you would never notice the ESP working anyway, if it came on you would be involved in some trickey manouvres that I suspect would mean you were not looking for flashing dash lights but instead preparing for a change of underpants when the car stopped.
You're actually pretty correct The only time I experienced ESP kicking in was when I made a sharp right turn way faster than I would normally do. I heard clacking noises coming from the direction of the brakes and yes, I didn't even think of looking at the dash As I was really unprepared for this, I can't really tell what happened with the car, but at one moment I was almost flying out of the road and the next - back on track. Good lesson learned - I would never try fast sharp turns again, except on a track...