Criminal Liability
I think you will find that if a direct correlation exists between a falsified weight and a death from spinning in because of an incorrect stall speed it is firmly in the realms of criminal negligence. The problem will lie in the criminal burden of proof that this was the actual cause. Haven't read the Coroners report or seen a recommendation for charges. As usual it will fall back on the civil burden of proof and the deceased's family will be left to slug it out with the no win no pay rape you brigade.
My memory is a little dim now but I think the J400 starts to skirt that boundary of stall speed vs weight at Gross in the 19 category, relying on so called flight tests to determine the observed stall speed. CASA has been ruthless during its recent audits with bull**** weights and RAA. Signed for a few reweighs caught in the audit where the original numbers were total bull****. As for C-150's being allowed into the category the Tech Manager at the time should have just held a gun to his own head, how fu@%ing dum was that?
At the end of the day you just cant beat Darwin's law, there are numerous examples of belt driven re-drives killing, and I am willing to bet that wing was slippery and had a nasty break at the stall.