First of all please count me in - if I ever snuff it in an accident, please speculate to your hearts' delight !
Secondly, IMHO this is
NOT about W&B but about density altitude and t/o performance in general. While the weight (or mass) part of the two obviously is related, they are two different beasts entirely. You can be well within W&B but don't have the power to achieve a successful t/o. It may well be that this is an area that's neglected in the UK, possibly because so much flying is done near the standard temp/pressure (15 deg C / SL). It is however, of importance not only in the US or Africa (where it is vital), but in many parts of Europe. As people can and do fly beyond the confines of the UK, PPL training there probably really has a lot to answer for.
In any case, a PA28-140 is not exactly the hottest ship around and with three adults and one adolescent plus (presumably) some luggage more likely than not was very close to MTOW. Add 10 degs above standard and a grass strip.....
