I think the moment you advertise anywhere you are asking for the Bold Gendarmes to come down on your head. They are in the business of reinterpreting rules then using our own money to drag us into court on frivilous charges. Having said that, there is also no point in poking them to see if they wobble.
There are a million ways around the covering costs of private flights; provided you don't go out of your way to see how far the rules will bend you'll be right. I once took a couple of mates for a free joyride then sold them an old football for $200. The point is that there was no intent to make money from the trip.
If you start advertising with the intent of making money and putting your own spin on the regs as a defense, then you're probably going to get in serious strife.
My thoughts only.
Walrus