This happens to me too, OP, and I find it pretty offensive. Not only do I feel like they are trying to find out if they can approach me sexually, I sometimes feel like folks are trying to find out if I'm traveling alone and hence an easy mark. I generally don't answer the question.
Sometimes though, women ask me, and then I try to use the conversation as an opportunity to encourage them to be fearless and to live the life they want to live (not the life society tells them to live).
Sometimes though, women ask me, and then I try to use the conversation as an opportunity to encourage them to be fearless and to live the life they want to live (not the life society tells them to live).