Have you shopped at an Academy store?
Every one that I've shopped seem to have unisex dressing rooms. They aren't even clearly marked as dressing rooms, in some stores....they're in the middle of the store, with a rack for hanging clothes that you don't want, at the entrance of the rooms.
I think most dressing rooms these days are unisex. Single occupancy and fully partitioned, it doesn't really make business sense to have them designated by sex.