>It doesn't matter that only 30 people might actually attend. Those who don't attend, the other 9,970 or so, will have no idea of that fact and likely will assume that as many people attended VFP session(s) as they saw in the session they were in concurrently.

A conference is a business like any other, and having the costs to have a session/topic/speaker where there are no (or just a few) attendees is not worth the cost.