Observations about Visibility

As I was teaching scriptwriting to the Film & TV students last Monday and Tuesday, I noticed something strange. The assignment was to write a short dialogue scene between two unnamed people, A and B. Each student could decide what kind of people these two characters were.
To my surprise, most of the students wrote scenes between two male characters. One group of about 20 students, for instance, had only two scripts with a female character. I asked the students if they had noticed the invisibility of women in their scenes, and they themselves seemed also surprised by the result.

This reminded me of many of the projects made by the media students. Not that females are altogether missing in those as a potential target group, but in many projects all people over 35 years have seemed to be strangely absent as intended users.
Again, I have asked for the reasons for this phenomenon. The answers I got were mostly that middle-aged and elderly people do not use computers, or mobile devices, or tablet computers. They don't read or write blogs either, or play casual games, or flock in social media such as the Facebook. It seems that this mysterious group is not watching television, either. Perhaps they really don't exist at all?

Okay, perhaps I've made my point clear.

I know that it is a big temptation to run along and do exactly like all others are doing, especially if you're in a hurry and the deadline is getting near. But there should be always a little time to step back for a while and to think things over. Is this really my target group? Am I missing or not seeing something that would or should be worth noticing? Are the things the teacher or some other authority is telling contradictory to my actual experience?

I really do expect you to tell me that I'm wrong or very inaccurate with these observations.