war1974:
its all well and good quoting mathematical forces shep, and I am really only playing devils advocate here. the majority of headboards if you hammer the brakes on and have a palletised load it wont smash the headboard or come out, its all well and good saying these curtains will hold x these y these z, when at the end of the day almost all curtains are held on by a bit of cheap metal on a rail ( yes they no doubt use stronger materials for these xl types) but if you have to stop in a straight line most will hold the load.the trouble is most of the shot loads we see are not people stopping in a straight line so it then renders the whole look at this tech pointless, and again I really do feel a lot is down to the driver and the current we can have any accidents society! if you have a load with straps on your still only strapping about 10% of the pallet.
I agree with most of what you say, especially about not being in a straight line stop but I am a firm believer that if we have the facts (known scientific facts) regarding the tested strength of items and the forces being generated and the theory of how the science/physics works we can then make educated calculations/decisions rather than guessing.
The mathematical forces I have used are proven. They are facts produced by scientific experiment and trial. A driver looking at a headboard and his load and thinking “That should hold it” but without the theory behind it means he is potentially guessing.
In the past I have had loads move/shift and a couple of disasters. At the time I never really knew WHY those things had gone wrong and usually simply put it down to something failed or was faulty or I didn’t tighten the straps enough. Thanks to now knowing the theory and understanding the physics I understand why those loads moved etc - it was because I was guessing at how to secure the load and I now know where I went wrong. My guesses were based on my understanding and knowledge at that time - which was clearly lacking!
Unfortunately two people can stand and look at a headboard (strap, curtain etc) and both come up with completely different answers as to its strength and possibly hugely different answers. Today I do an emergency stop and the headboard holds it. I now ‘know’ all headboards will hold the load - thsat seems to be what ‘experience’ means. However tomorrow the trailer I have is of a lesser standard - I can’t see that it is 1/2 inch ply instead of 1 inch and today I slam the brakes on resulting in the load over stressing the headboard - a small fracture appears in some of the internal plys but this isn’t visible on the outside surface of the headboard. I think my load stayed in again - phew. A week later, another driver brakes at a roundabout and the headboard finally lets go because it was weakened. He’s OK - just embarrassed, gets sacked etc etc.
We could go on for days. We all make our decisions based on our knowledge and experience. I prefer to throw a few facts in. Facts based on scientific trial and experiment. Saves me doing the experiments out there on the roads 
I too enjoy playing devils advocate … my favourite past time 