The problem is, MarySue, that once you go down the route of implied consent, where is the line drawn? And although some people could get along fine without a clearly defined line, others would push it as far as they could.
What actions would imply this? If a man and a woman are alone in a house, is that implying? Uh, no. Imagine how awkward that would make the gas man's job. If she's drunk? If she leaves with a man and goes to his house, many would say.
Oh, wait. Past story coming up again ... the first time I met my DP. We worked together in a night club. There were a few of us, and I happened to have offered her a share in the taxi home. Unfortunately we ended up forgetting her stop. So she ended up in my house, together with my brother and next mate who also worked with us and lived a few doors away. Was she implying that she intended to have sex with one of us? Actually, no, she wasn't. She explained to me later on that she felt quite afraid to be stuck with 3 men she didn't know very well.
I have a load more situations like it that were not implying consent. Therefore, just like the black and white line that is drawn at 16 years old, you should draw a line under consent and say it has to be had. If you really want to help to stop the instances of rape, or even alleged "crying rape" (which in man cases, I believe, are down to her being to afraid to say no as she is afraid they will take anyway), then you would agree to a slight break in the flow of things to help get a place where there is an agreed consent.