I am convinced the biggest risk on aircraft weight remains the under-calculation of pax + carry ons. This despite the recent mandated FAA et al increases.
In 2013 the H&S dept of our N. Canada mining operations did a full verification of our rotational personnel. Yes, these flights were over 80% male and miners are probably larger than the average male, but....
The result???
Summer 278 lbs.
Winter 291 lbs.
Enter those kind of figs into the last Weight & Balance you personally calculated and you'll see where I'm coming from.