I rarely take someone as a passenger, and when I do I can tell during the pre-ride how they might be and have often changed my mind and not taken them. I also hate the term backpack. No, you are an active participant in the ride and if you want to be a backpack the answer is no. I want to add, this does not apply to just women, it would be men too but you know - most men will not ask to ride as a passenger on a bike.