Talking to them today, they have no pictures, and the setup was taken off after harvest, so no pics
As well as the pipe incident, they also had the bottom edge of the thresher bar hook on the square edge of a rock, which pulled it out of the ground, jammed the flap under the wheel, bent the mount bar and then ripped off the flap.
A few lessons they learned :-
1. The concave bars (bolted back to back through the bottom of the rubber flap) were a good idea for preventing wear on the flap, and adding weight to lay over the stubble, but they proved to be the achilles heel for hooking onto objects. They are thinking of mounting them a bit higher up on the flap, and just letting the rubber wear.
2. A handfull of cable ties take a lot more force to break than you might think! Start with less and add more as required. Fixing a wire from the centreline of the machine to the inside of the flap should stop it getting lost while you are working out how many is right.
3. After the second incident, they mounted them on the rear of the comb. On their machine they are not able to mount them any further forward on the feederhouse, and they felt it was just too close to the wheels. They don't do as good a job while mounted on the comb, as a certain amount of stubble will spring back up behind the flap, but it still does a good job. Mounting the bottom edge of the flap closer to the wheel lays down the stubble, and the tyre irons it flat before it can spring up.
Closer = better performance in shorter stubbles, but more chance of a rip-off. Everyone will find their own distance by experience
Hope that's some help. I'll quiz them a bit more over Christmas.