It would be nice if you could opt out of being displayed in Flight Radar 24 or similar. Even the police appear in there, albeit with their aircraft type showing and not their rego in some cases. AvTraffic has no controls, all of the police aircraft show up in there and I've literally seen a bunch of Eshays at an Oakleigh restaurant showing each other how to see where the police helicopter is by using AvTraffic. If the gangs out stealing cars know where the air wing are, they cease and desist as they know they will be busted very quickly otherwise. The AFP Survey 400 a C208 flies without showing up, but that's because they turn off their transponder and they are tracked as a primary paint by Mel Centre in a block altitude not below 8,000ft or thereabouts.
That seems complicated for thieves. Why not just look for the driveway to be empty? Vastly increases the options for burglars.
Not really. If you watched aircraft taking off out of Moorabbin registered to a private owner, you can drive on over and if there's nobody home, there's a high probability you know exactly where the home owner is.