They could do a lot of clever stuff, maybe a different compression ratio for each participant. Even the arangement of the participants thumbnails on the screen,

They could do a lot of clever stuff, maybe a different compression ratio for each participant. Even the arangement of the participants thumbnails on the screen, if I were working on the "leaks mitigation" team I would suggest the server to store the arrangement per user, and if the user switches the faces around on the client app, to also record that order!