Luvvie Ajayi (supposedly a pro), claims on her TED talk that she wasn’t offered pay because she’s black female. Yet, she herself contradicts it in Forbes. https://www.forbes.com/sites/christinawallace/2017/03/13/pay-gap-for-speakers-at-tech-conferences/

“Another prominent speaker, author, and former tech executive weighed in: "I've checked with several of the men who have spoken and it's 50-50 whether they got paid. So it's not a 'policy' to not pay; it's just policy to try and get people for whatever cheapest form they can so they can make money off that talent."