I was invited to be on a panel at Defcon in Las Vegas, so I travelled domestically to speak. The event gave me a free ticket, and I was not paid to speak. My travel and accommodation was fully covered by the event. My employer did not pay my travel expenses, and I was unemployed when I spoke at the event. It took me 2 hours to prepare for my 1 hour speaking slot, and I had a mostly bad time. I'm a man who has been speaking for 6 months. This was a for profit event.