While I have not seen any reliable figures it is a "well established" fact that the high period of risk for private pilots is in the 300 - 400 hour period.
I suggest that this is when one has moved from the only flying in perfect conditions to gaining a little more confidence that they should have (I am low 300 hours and experienced such a thing this Saturday in Martinique - very dodgy weather, I was 1800ft 3 miles from the airport in and out of cloud and about to call it quits and fly back home when a large gap appeared - when I was 200 hours I likely would not have left home due to the 1400ft broken cloud on their METAR).
These issues of numbers are not the issue here. I as 200 or lower pilot would not have flown - but what if I had people I "had" to fly - that 'pressure' would slew the numbers - that's the whole point, not can someone fly in their local area - yes certified, but rather the judgement of should I or should I not do the flight, especially with someone I may be letting down; thus getting into a situation that I cannot (maybe by the skin of my teeth) get out of when the decision proves a bad one.
There is a whole lot of officious stuff that goes with flying no matter where one flies and under what regulations - the no paying passengers without additional training and certifications seems to have stood everyone in good stead for decades. The fiction of cost sharing is just that, a fiction - looks at some of the prices people are quoting, no way is the pilot paying his "share" are seems to be making a nice profit from it. As I said waiting for the first deaths from one of these wheezes, the company will likely disappear, and the relatives will, I suggest, have a pretty good claim against the regulators who permitted it to happen.