https://arstechnica.com/information-technology/2019/07/zoom-makes-it-too-easy-for-hackers-to-access-webcams-heres-what-to-do/

One of the easiest ways to tell if someone is a practitioner of computer security is to look at their laptop. If the webcam is covered by tape or a sticker, they likely are. A recently published report on the Zoom conferencing application for Macs underscores why this practice makes sense.

Researcher Jonathan Leitschuh reported on Monday that, in certain cases, websites can automatically cause visitors to join calls with their cameras turned on. It's not hard to imagine this being a problem for people in their bathrobes or in the middle of a sensitive business conference since a malicious link would give no warning in advance it will open Zoom and broadcast whatever is in view of the camera.