Disabling participant webcam

For security reasons, as a host of the meeting it might happen I’ll disable some participant’s webcam. So he/she will not able to share his/her experience (audio and video are off) but can keep listening and be part of the meeting.
We’re an association of recovering addicts who meet regularly to help each other to stay clean by sharing our experience, problems and hope.
We let any drug addict attend our meetings but we ask them not to share if they get high. Moreover, if they are actually using any drug they can still attend but we cannot allow them to show drug use related scenes.
Anyhow we don’t want them to miss the meeting if they want to. So just disabling webcam and not to kick off would be (literally) vital.