I'd be willing to go to an event like this for free, if I knew there was a chance of getting clients, and if I knew people would behave in respectful ways, but I'm not so sure that the people who would show up would be interested... And it's like you're saying, most providers wouldn't show up if there was no compensation
I said it more as a reality point to the thread and what is being asked to be planned.
I might chose to go to something like this just out of curiosity. But from what I have come to understand of events like this. Part of the cover charge at the door goes twords incentive also for providers to make an appearance, even if it isn't much. It takes time out of their day they would be available for others, with no guarantee of securing further earnings that night.
The providers at these events don't just happen to show up unexpectedly. Maybe, but I highly doubt it. If it is just for exposure, without any compensation, this type of event is likely to just become a sausage fest with maybe 5 providers making an appearance.