People also walk around with their phones out so often. There's no way for you to know that they aren't recording. E.g. someone could easily be pretending to use their phone when climbing stairs while actually taking upskirt shots with the front camera.
Social media is also already full of people shamelessly recording others in situations where they would not want to be recorded.
Actual perverts have little reason to use these glasses specifically, and as mentioned in my previous post, the cameras have utility other than recording others.