An interesting comment thread has cropped up on the LiveJournal polyamory community in response to an advertisement for "poly speed dating." The event (but, strangely enough, not the advertisement) had a caveat that "solo men who are only looking for women" are no longer permitted to register.
I'm of two minds about this sort of thing. On the one hand, while there may be a bit of indignation (since I'd likely be among the excluded group, and that rankles a bit even when it's an event on the other side of the country) I can see the reason for this; it's going to be a bad time for all if there's no attempt to balance the genders among the het-only folks (from what I can tell, the event isn't itself restricted to het dating; if that's the case, I'd love to see their algorithm).
On the other hand, a lot of these sorts of things wind up taking an overtone of commodifying women; the entry fee for men becomes "$12 and a woman." And in addition to being generally squicky, the people this brings in are not necessarily ones who are particularly interested in the exercise; it doesn't solve the problem if the het side of the speed-dating event is full of people who may not actually be interested in dating anyone.
I should acknowledge that closing admission once there's an imbalance is very different from closing admission from the outset. In the latter case, sometimes it may be based in a correct assumption that such an imbalance will occur, but the impression I get a lot of the time is that it's something like the highly patriarchal polygamous communities that routinely cast out men from the group to make sure that those men who remain don't have any "competition."
So what *is* the best way to handle this? In the long run, I think what's needed is to reform attitudes; I have a suspicion (totally unsubstantiated, of course) that if you took away the subset of men who are just looking for any way to get laid, and you added in the subset of women who would be interested except for those men or societal pressure, the numbers would be pretty well-balanced.
In the medium run, what's needed is to foster an attitude within the institution that everyone is an agent rather than a commodity.
In the short run, it's pretty much up to the organization, and it seems to break down into a classic utilitarianism problem - do you do what's immediately best for the most people (i.e., restrict solo het guys for the benefit of everyone else), or adopt an approach that leaves fewer people singled out (so to speak) but negatively impacts the event for a lot more?
1 year ago