I think this could depend on where you live (& possibly other circumstances)? I know plenty of folks around me with cameras - inside and outside - or doorbell cameras these days, whether they’re for security or to keep an eye on their pets. I definitely don’t think it’s the majority at this stage but given that it’s generally affordable and easy enough to DIY these days it’s becoming much more common.
As a person with something pretty significant to hide (and likely a lot of disposable income) I wouldn’t be surprised if Lynn had cameras (or at least a less fancy security system) at his place in Caroline Springs.
Having said all that, when I remember that this all went down almost 4 years ago, I think it does make it much less likely that CCTV would have been an issue.