Anybody can apply to do an event at gencon.
There are 300 seminars listed here, Patrick is on three of them
Entertainment at the end of the world: 28 tickets sold between 5 speakers
The long tail of publishing: 28 tickets sold between four speakers
Handling book releases: 10 tickets sold between 5 speakers.
I say "sold" even though they are free events. GenCon do some kind of reimbursement for other events based on how long they are and how many people attend, but Patrick won't be seeing any of that money. 50000 people go to gencon, Patrick can't convince 30 of them to listen to his bullshit.