you're right of course, this wasn't a cost-sharing flight, but that's not to say it it wasn't being flown under the auspices of being one. The FAA state for a cost sharing flight that the direct costs are borne by the OCCUPANTS of the craft (up to a maximum of six) on a pro-rata basis. A third party paying for the direct costs would not meet the cost-sharing criteria. But then the corollary of your point is that the pilot knowingly flew a commercial flight and portrayed it as such without the necessary licence which I find extraordinary.