Just spitballing here...

What if in the pre-registration package there was a one-time bourse floor free entry ticket that could be given to anyone. Members could keep it in their pocket and if they meet someone over the weekend that sounds interested or intrigued (tagalong friends, fellow gamblers, people in the cafe, etc) they could hand it to them for a one time entry. The guards at the door could collect them, or tear them, to make sure it wasn't reused.

I know if I was gambling next to someone who was talking about some obscure hobby (i.e. meteorites, antique watches, etc) I might think think it was neat, but probably wouldn't pay an admission to get in. If that guy handed me a free ticket, I would definitely take a look. Who knows, maybe someone would get hooked.