You would need to post pictures of the men's and women's US pants you see being worn, for me to make a determination whether they can be adequately distinguished from each other or not.
Do women in Canada not wear pants?
Yes, but you were asking my advice and I didn't want to presume that what you were witnessing was what obtained in Honolulu, for instance, or Turkey. Many a conversation becomes heated and boils over the top of the pot because someone or other makes the mistake of presumption. Show me the pants, and I'll separate one from the other, if it be possible or not. Remember, I'm guided solely by the Biblical principle:
for Christian modesty and gender distinction.///