Judy: I haven't had that experience but that just sounds like a good idea to me. That would help get the wallflowers engaged. Often, breaking the ice is the hardest part. I've been at vanilla (Non-swinging) social events where the host took charge and got people hooked up to socialize and dance. I can see where that would be really helpful. It would be very important for that person to have very good "people skills;" be encouraging without being demanding. It just sounds like an all-around good idea to help people have a good time.
Although I doubt the brochure said this, you can bet they were also there "policing" the area and were there to intervene if someone was acting inappropriately. That's just good policy.