It is illegal to record someone without permission in particular on private property. It is illegal to record children. There are major implications if illegal activity is recorded. Are you responsible if you don't notify police about a crime. Then there are the myriad of social concerns. If you record me and for privacy reasons I want the video erased how can I do so ? Or am I forced to remove the glasses from your head and destroy them?
Just like smartphones are required to make a noise when taking a photo I wonder whether there should be a red LED light to indicate when recording is occurring or a button to erase the last 5 minutes of video.