> I'm not sure that's the standard you want to base this argument on, because in most cases, the "professional approach" amounts to "if you come here at all, you're consenting to be photographed for publication, take it or leave it lol". FB had a stronger standard than this.

It depends on the event and the nature of the venue. But yes, it is a bad analogy. For one thing Facebook is not an event with clearly delineated borders. It should naturally be given much higher scrutiny than anything like that.