Tried an open call for a committee meeting where everyone in membership was informed they were welcome to participate - and given the date, time and location. Got a very knowledgeable group who made excellent recommendations; and participants included those we would not have thought to invite. However, it was a really small group.
If we ask 10 specific people to participate in a live meeting, typically about 8 are able to do it. If we openly invite 4700 we get less than that? Although I'm not sure if we had invited 10 specific people if they would have done a better job than the ones who self-identified for participation.
If you've tried it, did you get similar or different results?