I think the type of crash bars may make a difference too. The ones in the article were the kind that extend out perpendicular from the frame, and then wrap around the cylinders. I have seen them before, mostly on the oil heads. I could them getting caught on a low-side and causing a high side.
Then there are the other kind, that only extend out perpendicular from the frame. They do not wrap around the side of the cylinders parallel to the fram. These are what BMW offered back in the early 1980s. The likelihood of them ever getting caught is a lot less. Also, no need to remove them for valve work. I have a set of these, and they have saved the heads and valve covers from a lot of dings and scrapes and possible damage. Face it, everyone drops a bike a few times in their riding career, and it does prevent some damage.
k_enn