I think I have broken one front spoke in some 350,000 miles of riding but maybe that was a hub flange failure (I know I had the hub flange failure so maybe that was the only "broken spoke") In other words it's a VERY rare event. Possible, sure but a front tire blowout is MUCH more likely and that would have more serious outcomes on a descent. I have had front tires go soft on a descent but never had one blow out so that is pretty rare too.Never had it happen to me, but for some reason it is my worse fear, so I usualy run 24 if possible.
Anybody ever have one break while decending?
The number of spokes may affect how far the wheel goes out of true if you do break a spoke, but as several people have said, this is a rare event.Hole count is not really a factor when breaking spokes. A well built 16/20 wheelset will be more durable than a poorly built 24/28.