This conversation today is why I boycott not only events who do not pay speakers a fee and expenses, but also events that do not charge an admission fee. Along with big budget media outlets who do not pay technicians and creative folks for their skills. EVERYBODY deserves to be paid for their work. The days of artists, bands, authors, creative folks and dedicated researchers giving away their hard work and skills in order to 'get exposer' is over as far as I am concerned.
I would like to see the organisers of this event telling a plumber who came to their house that he/she should fix a leaking pipe for free as it will 'spread awareness' about the plumbing profession.
I've already given away vast amounts of my knowledge, music, art, comedy and insights and help to thousands for free. I can't pay my electric bills with a 'Namaste'. Nor should I, or anyone else be expected to do so. It's not greed, it's basic living survival.