Although a general group gathering would definitely be preferable to something where people have to pair up--I'm not sure if I would prefer to know that there was a "potential match" in the group or not. On the one hand, knowing in advance would definitely make things a bit awkward--"Oh, you're the guy she thought I might like. Let us now proceed to judge each other." But on the other, there's every chance I just wouldn't attend a social event I was invited to, because I didn't know there was anything "special" about it. Kind of like if a couple springs a surprise wedding on guests at what was supposed to be just an ordinary BBQ, and some guests who declined are mad because they didn't make much effort to attend, thinking it was just a BBQ, and now they've missed the wedding.
There was this male friend a co-worker kept talking about once, and one day she said that he was thinking of taking a class I had already taken, and would I be willing to have lunch with him and tell him about the class, so he could decide if he was interested in it? I said no, because I wasn't going to have lunch with a total stranger--plus, I'd never heard of anyone investing that much time to investigating an ordinary, undergrad college class (lecture-based, not like a field trip overseas or something). I said we could exchange a couple emails about the class instead, if he had questions, which is what happened--one email from him, one email from me, thanks from him. The end.
Later another friend told me she wondered if the lunch thing was supposed to be a set-up for a date, which I completely (and unknowingly) blew out of the water. The co-worker claimed it wasn't and that she wouldn't do such a thing without checking with me first; looking back I kind of wonder about that, because the way she described him was superficially similar to me, and it was just such an odd plan on her part. But, weird stuff happens sometimes. I wouldn't have agreed to go on a lunch date with him anyway, if that was the plan and she'd told me in advance; I know that's the whole idea of a blind date, which some people enjoy, but I think I would be very uncomfortable with it. Plus, frankly, some of the stuff she'd said about him did not seem very positive or flattering to me.