And there is zero reason parents cannot be participants. We have all seen what the schools and law enforcement and universities do when they are not monitored by their supervisors... the parents.
People there are parents. You think law enforcement people don’t have kids. And no, they don’t need to be there for this conference. It is not about them, the venue won’t hold them, and it would increase the cost.
All kinds of agencies have conferences. They are not open to the public.