Hotel door hacking and how to protect against it ...

Something one needs to be aware of when the doors in use are electronic doors. If you try to open the video on youtube, it says that the video is unsuitable for minors and asks you to login with your gmail account to watch it. That doesn't make sense, kids below 18 should be aware of the attacks and how to protect themselves. Understanding the attack itself will allow the viewer to think of more than one way of protecting themselves and understanding the risks.