Private flying's risk profile is hugely dependent upon the PIC.
Do you chance the weather, or do you wait for perfect days? Even if the latter, would you struggle with deteriorating weather or unexpected x-winds?
Does the PIC have 50 hours or 5,000 hours?
You're wasting your time with trying to find real evidence to back it up.
Ultimately, if someone's THAT worried about the risk, I'd suggest they're probably not going to enjoy it that much eitherway.