"Surreptitious recording" refers to secretly or discreetly capturing audio or video without the knowledge or consent of the people being recorded. Full definition
What Jinkis didn't know was the FBI was also listening — through surreptitious recordings made by an associate. (fortune.com)
In the past, BC courts have been disapproving of surreptitious recordings in family cases. (hhlaw.ca)
That was a bit of an unnecessary clarification, though, given that the question was about surreptitious recording, not something users were explicitly recording media to share. (techcrunch.com)