Disable webcam

sudo lsmod | grep uvcvideo

you see (example)

uvcvideo 114688 1 videobuf2_vmalloc 16384 1 uvcvideo videobuf2_v4l2 28672 1 uvcvideo
—– more stuff possible —–

Now, disable webcam.
Edit the following file (if the file is not exists, just create it):

sudo vim /etc/modprobe.d/blacklist.conf
##Disable webcam.
blacklist uvcvideo
save and exit editor.
reboot your system
Start cheese and you see a black screen with says “no devices found”