FOSDEM organiser since 2001 here.

I'm sure you meant to help, but a factual inaccuracy crept into your comment. FOSDEM has never ever scheduled any talk or other content in exchange for money. There is an absolute consensus within the organising all-volunteer team to stay that course.

Our goal is to bring free and open source software developers together at a yearly conference. We manage income and expenses very carefully, eliminating any need to compromise our mission by selling talk space.