Seriously, who needs to record someone without the knowledge of the person being recorded? That’s a big red flag, a perverted character, there’s no other explanation. Creepy Mark Zuckerberg allowed other creepy characters to share personal moments with him.
In Germany they’re called “Spannergläser” that translates to “peeping Tom’s glasses”. Heard that term after the first guys tried to wear and use them around public pool areas.