With the help of a jeep-owner backing out in front of me this morning, we were able to field test the H&B engine guards for a low-speed drop.
I had slowed down to almost zero by the time we went down. There was no contact with the other vehicle, but about 20 feet of skid mark from the rear tire, and a foot or so from the front.
I couldn't find any visible damage other than the crash bars themselves. The bike took a few cranks to fire up again, but I let her rest for a couple minutes, and she fired again on first try. I've ridden around the block a few times & everything seems smooth - no funny noises or weird behavior.
I couldn't even find any other parts of the bike that were scraped up by the pavement - not even the top box, front axle sliders, or handlebar ends. This was probably because the drop was on a downhill incline, & the bike sort of balanced itself on the crash bar at rest.
Anyways - just figured I'd post a couple of pics, because I bought the bars as a sort insurance policy, and this makes me think they were an excellent investment. I'm going to go ahead and speculate that I would have taken some damage without them.
Off topic: This was my first drop ever (3 bikes, 20+ years) - so I feel like I earned some kind of badge of experience today.
It was much harder to pick up the bike than I would have thought - I had to try a couple of times, then turn around & do it the squat-style like they show in the police rodeo videos.