I haven't technically validated it, but it looks like this is also the case for the Matrix protocol. If a user is in a public room, then their presence gets enc

I haven't technically validated it, but it looks like this is also the case for the Matrix protocol. If a user is in a public room, then their presence gets encoded as part of the message history. If the room is fully public, anybody can come along and get the historical info. It's possible to turn off presence but only on the server level.