Do you see that this could possibly be a serious problem with SKYPE?

To take a semester exam the student has to be onsite or on SKYPE so’s we can watch them. So far everyone has elected to come on site, and I’ve never used SKYPE before except for a few test runs with a tech months and months ago. Well, today I had a student who wanted to use SKYPE, so they went out and bought the camera and software. We were on the phone with each other, both of us kind of fumbling around trying to get connected. We were making some progress when suddenly I was looking at HIS computer screen on my screen! I told them what I was seeing and asked if the camera was pointed at the screen. It was not. I was a little freaked out, and thought perhaps I was mistaken. I watched for a moment more as their mouse scurried around, then I said, “OK, you have your homework in the background…um, English II, but you have SKYPE in the foreground and you’re clicking on ABC.”
He said, “Yes! That’s exactly what we’re doing!”
I said, “Yup. I can see your screen and I’m outta here!”
I X’d out (still on the phone with him.) It was something they did unawares…and to me, that’s just not a good thing.
What are your thoughts on this?
Also…do you think this is something I should bring to my boss’s attention?