I ask the question mostly with the design concept of reducing weight in mind. Sure a double layer 1000 cordura might never fail but as a backpacker I personally try to reduce weight. So any piece of gear I carry I try to trim weight while maintaining most functionality.
If a single 1.1 never fails then I would make it out of something lighter. Also if they fail in certain places then perhaps I could add reinforcement only there like on how they do on a shoe upper.
I push the limits of seeing what is the minimum I can get by with is. So with that I can safely say that all my failures are my own fault in one way or another:
1. Rope failure - using rope rated to 400 pounds.
2. Strap failure when a strap sawed through itself - I think that was using some strap I found in Iraq when I couldn't find something else.
3. Rope failure - using rope rated below the safe margin (500 pounds I think) and it failed just below the knot, where all literature tells you a rope will fail when it does. The cool thing was that the rope had made it about 750 miles at that point. I think if I had spliced that instead of tied it, it might still be working today.
4. Body failure from friction with stuff in my pocket when trying to make a hammock out of material lighter than 1.1.
5. Body failure from a design idea I had: foot and shoulder pockets to make a short hammock feel longer. It worked for a few nights but eventually gave out at the joint of the footbox on the side I normally sat on when using it as a couch (and it was very uncomfortable that way BTW). It happened at night, on the trail, during a rainstorm, over a piece of unlevel ground - so I spent the rest of the night trying to stay dry and get some semblance of sleep. So design failure.
6. A friend trashed a Hennessy of mine by hanging it to where his butt kept scraping the ground and he didn't fix that issue. I don't know the details because it was one of those things where you loan someone something and then don't even hear from a guy for about a year, and when you do he is handing you a screwed up piece of gear. It failed across the body and you could tell he had been doing that for a while because there was a great deal of sign of damage across the butt area where it had scraped back and forth for a long time before something finally gave. I credit that one to being too lazy to get up and fix something that should have been corrected right away and then changing how he tied the hammock so it wouldn't do that again.
I've never had a hammock fail that was designed properly and used as directed.
The "Search" function is your friend!
The only way to protect yourself can is to make it out of 1000 Cordera. That will. E your only security if you leave you knife in your pocket or your keys. Other than that there is no way to protect against human error.
You are right you wouldn't blame the car but also a car doesn't fail if you drive it off a bridge and it doesnt float. You learn not to send cars off bridges.
Second possible solution is to maybe adhere the fabric in strategic locations. No needle holes.
I'm uncertain if the stress on the fabric is uneven to even warrant specific location reinforcement.
I think I remember an HFuser reporting his hammock failed about 12inches down from the knot on the hammock body. Not from abuse.
Basically my methodology is use the lightest fabric until you get failure. Then you add back fabric. But if the hammock stresses in certain areas then only add back fabric in those areas rather than a full layer or heavier fabric. This is more in the spirit of pushing performance like a hammock for and adventure racer or thru hiker.
A pity more has not been forthcoming; because there is a lot of customization requiring sewing which people may not be undertaking for fear of failure in the body. Clark has long been sewing their lightweight pockets right across the hammock bodies and in high-stress and maximum wear areas with 6 stitches per inch with small risk they are willing to take.