At my club, when the subject comes up for discussion, it is assumed that the pilot must pay a proportion of the cost of the flight to stay legal. Free flying, I was told, is a no-no.
That's a reasonable way of describing the cost-sharing exemption, so I'm not surprised it's simplified in that way in the club; but as we've discussed, other exemptions exist, such as that allowing the pilot's employer to pay all the direct costs.;