I'm gonna agree with the others and that the durability test did not test the limits of notebook.
All of the tests should have been conducted when the system is on, and running a CPU/GPU/HDD/ stress test (and constantly reading a CD at 48x), running in an infinite loop. The notebook should have been dropped from 6' onto a corner, landing onto concrete, instead of the plywood--as this would replicate more realistic conditions.
With regards to the liquid spill test, again, the system should be on, and spilled with 20oz of soda and it should still be functioning. Better, pour soda all over it, and then start spilling gallons of water to clean out the soda in the system, while the system is operational.
With regards to more "office like" conditions; (again, while the system is on, running it's stress tests) the note book should be stepped on with one foot, by a male that weighs around 180lb, it should face the power-cord trip test, and be toss down a flight of stairs, from corner to corner.
Also, intentional damage should be replicated, such as take the notebook and throw it towards a wall out of pure frustration, it should also take a 20lb sledge to the notebook, to see what kind of damage it can with stand.
As a measure of durability, the notebook should been tossed out of the tallest sky scraper and see if the HDD is still readable.
Oh also, drag the notebook through mud, sand, and water...
Another note to the stress test, the notebook should be open, with screen at "normal" viewing angles, when performing drop, kick, run over tests....
Just my two cents....