I saw from close behind an incident.
An experienced rider dump his Newton (upright 2 wheels at front) trike into the hedge on a straight descent. At the time I'd caught him easily on my tadpole (2 wheels at the front) recumbent trike. He braked, he must have been doing 25mph, one of his front wheels locked on some gravel in the centre of the road, and that was it he went over the top as the trike hit the hedge. I stopped immediately to help, one of my front wheels locking on the same gravel and I hopped off to help him.
The difference? My backside was 8" off the road and his was at normal upright bike height and my trike has independent front brakes, his had linked. So when his front left locked he turned hard and had to release both brakes, and was then too late in getting his brakes back on. When mine locked I automatically released the left brake keeping the right hard on, then reapplied it. I pulled up safely, he went right into the hedge.