It's funny people think this is not a security issue, because it is and you will soon read hundreds of stories of how someone's iPhone 5S was broken into at night.
Even if you are a light sleeper you will not wake up if someone takes your phone and holds it to your finger. There is little pressure needed. What could go wrong? Lets see...
1. Someone can send emails on your behalf.
2. Someone can take photos of you or steal photos off your phone and email to themselves.
3. Someone could send Tweets from your Twitter account.
4. Someone could post content on your FaceBook page or even remove/add friends.
5. And, if you're native enough to have bank account apps on your phone...well, that's all I need to say.
There are hundreds of things that could go wrong, and don't think adults don't have roommates. If you do you clearly have never lived in a major city. Also, most college students have roommates.
Just watch. The stories will be rolling in. Will be entertaining.