As a private pilot for the past twenty-something years, I generally agree with the FAA’s position on cost sharing and “holding out”, and I appreciate the difficulty in defining which is which.
There is a clear difference, in my mind, between being able to take a couple of friends along for a $100 hamburger or on a weekend trip to another city and sharing the flight costs, vs. posting an online ad looking for someone that might want to ride along to Nearby City and share the costs. In fact, I’d say almost every instance in which you would contemplate cost-sharing with a complete stranger seems pretty suspect as more of a business transaction than “cost sharing.”
Mere mortals – i.e. non-pilots – know nothing about the legality of any of this, and if you offer that ride to Nearby City for only $100, or whatever, somebody may snap up that great deal, not really understanding that you’re not legally able to offer transport services for money. We probably all know private pilots who we wouldn’t want anyone we know to fly with, for money or not. There’s no way for some stranger to differentiate between a safe plane and pilot and an unsafe one, nor should they have to.
I looked at a couple of the internet-app based “cost sharing” services that previously existed, and it seemed really clear to me that what they were offering was clearly on the wrong side of the grey areas of cost sharing. This is one of those situations where it’s fairly easy to see what is legit cost sharing and what isn’t, but it’s a lot harder to define it in a way that works the way you want it to. I appreciate that the FAA has left the definition fairly nebulous, but of course it’s inevitable that some use that imprecise definition to try to justify what I see as bad behavior.
The comments here about Part 91 vs. Part 135 are interesting but really have little/nothing to do with the subject of the article.