Oh ffs, Just give her a friendly tap on the bum and tell her you agree with her.
I just don't see how that isn't intrinsically sexist.
I think in this day and age men could choose to accept the role of the gentleman, giving up seats to young women and all that.
I suppose you could argue it's somehow "post-feminist" - recognising the equality of women yet embracing the spirit gentlemanly behaviour at the same time. That just kind of feels like bollocks though.