Both of those responses are good. My experience comes from political events, where often the pols would want to be seen and heard (mostly).
I think video could still be made available during open time, so that those who can't make it can still join in a bit of the fun. If events are being handled by attendees just for the sake of being there (such as Dan's balloon jams), I don't think they would have a problem.
But yes, professionals do need to get paid. That's where the costs will creep up. I don't think any merchandising should interfere with the vendors, if it's kept to things like clown forum hats & shirts. But again, not sure if it would be worth the effort. If there were a dvd afterward it would have to be a highlight film, which would end up being more of a advertisement for vendors and lecturers more than anything. And would have to have review and authorization.
Sometimes I think it's actually easier if you're planning something with hundreds of attendees, you have more leverage to work with!
Then again, I personally would be more than happy to have a spring fling with no formal agenda or presentations. It was just nice to go
