I just got round to reading the membership pack of leaflets I handed, and it turns out that they have a tonne of "ladies only" classes, including the "Pump It Up" ones (which I'm guessing are BodyPump minus the franchise fee).

So, yanno. If they're okay with women-only classes in principle and think that's a useful strategy, they could timetable a women-only session for the free weights room. But I bet it didn't even occur to them.