First off, surely there are other reasons someone might be touching their ear?
Secondly, what use is a mobile phone without the infrastructure to allow you to use it? You could argue that perhaps the woman is from the far future, and using some freaky future technology which doesn't require masts and cables and big computers, but if so, how likely is it that the futuristic device would be something you hold up against your ear? The trend is towards smaller and smaller devices, often ones you can just plug in to your ear and forget about, and I don't see that reversing in the distant future.
Sorry, I just don't buy it.