I often go "ladies" when the other one is full.
Oh hell yes, no shame there.
I even have a line that I use when women ask me what I am doing using the ladies room. (as if I am required to defend myself to them)
I tell them that, "I have really horrible gas today and didn't want to smell up the guys room, the place is all yours Hon !"
The looks on their faces are priceless. Hoot !