100 "bucks" for 1 person or a couple, or are those events you are talking about generally free for women?We would pay -similar events in Germany are up to 100€/dollars ...
i tried to estimate the costs and it seems with the exact concept presented in my posting above it wouldn`t pay off. Of cause it depends on the constellation and other factors too. But i think it would be too expensive to get people to actually take part if (a) the overall number of participants was too small (which would eliminate a situation with only one female attendant), and (b) the relative number of passive attendants (spectators) was too limited (which would be the case - in the example situation - with 5 females, 15 Black but "only" 5 to 10 non-Black males).
i think it would be possible for the other cases (2-4 females, ...) to get to acceptable prices (from approx. 125 to ~150 "bucks" for a white couple (both), for instance). This could be rapidly decreased if the policy would change to BYOC (in which case the same couple would have to pay no more than 80 "bucks") or if there was a sponsor.
But one of the biggest problems is to establish a group of people with interest, and the far bigger problem to find the right number of people who will actually show up. ;( Oh, yes, and then there should be someone who organizes the "damn thing" (including finding a suitable location) for free.