According to the SHB (p.10, Category Matrix), black powder categories can be condensed to non-black powder categories. So for instance if there is only one Lady Frontier Cartridge Duelist in a State or Regional match she will be collapsed to Lady Duelist even though she shoots black powder. And if she's the only Lady Duelist (or one of two), they will be further collapsed to shoot in the Duelist category because it is the base Open Category. There was talk recently that match directors have discretion when it comes to categories, but according the SHB, they really don't. They have discretion to offer categories but can't honor categories that have less than the required minimum participants. SHB pp 10-11. So in my example a woman shooting black powder could be forced to compete with men shooting smokeless. I don't know of a match director that would do this but that's what is written in the rules.