Depending on group privacy, they may be able to identify members without joining it (i.e. no need to hack someone else in the group). I haven’t kept up on What

Depending on group privacy, they may be able to identify members without joining it (i.e. no need to hack someone else in the group). I haven’t kept up on WhatsApp research but at some point this was true - same goes for online status and avatars. I have those set to “nobody” and “default.” WhatsApp makes it way too easy to go from “phone number” to “real person online at X, Y, Z hours.”