The second part of squawks post describes the long held FAA position so I doubt they will have much of a chance in these circumstances.
I flew in USA for years and they are very strict on people trying to set up pseudo charter type operations in place of a private op.
Charter operators could try and sell empty seats on certain sites to try and fill them on empty legs of existing charters etc.
Here in Aust, if I post on my FB page I am renting and flying a plane to Woop Woop on such and such a date /weekend and ask if any of my friends want to come along and share the cost I think that would be legal as I am NOT a commercial business, and only my friends can see the posts, NOT the public. ie it is not "Holding out".
I have a document somewhere that explains what the FAA considers "Holding out" as naturally it is NOT defined in the FAR's. That would make it a lot clearer if it was.
Also I have an ATPL, not only a PPL, but of course that doesnt mean I can offer a "Charter type" service without an AOC in any country.
I think the Aust Regs define what constitutes are private flight reasonably clearly, been a while since I last read those specific sections.