Now anyone can subscribe to 360radar, but it is limited to the UK and a small part of northern Europe. It's not the cheapest service, but if you're an aviation photographer in the UK it and its linked community are a key resource.
That wouldn't stop any traffic collision or ATC function from working but would prevent persistent tracking of for example private jets.
As a pilot, it's valuable to be able to see tail numbers to help correlate what I'm hearing on the radio with what I'm seeing on my displays. I can guess who's who from position reports, but seeing the tail number leaves no ambiguity.
There are also some smaller facilities that use ADS-B to monitor traffic, but aren't networked into the national ATC radar system.
Aviation events will also setup their own temporary control tower, and frequently use ADS-B as an aid for sequencing traffic. (Again, without access to the national ATC radar network.)
For folks who need privacy, there are a couple options that already exist - UAT privacy mode or private Mode S addresses. Though notably, both of these are only available options for domestic flight within the US.
Why? They are using our airspace. Looking down in to our backyards. I have a right to at least get an identifier I can use to report to authorities.
I've worked with VVIP executive protection teams before and if the trip needs to be secret they will schedule plane swaps along the trip or rent a jet that is not attributable to the company.
Having to coordinate with every ATC jurisdiction along a flight path would be extra work and leave room for errors.
Additionally it wouldn’t work for flights that don’t have a planned route, like a civil aviation pilot who’s just cruising.
It’s akin to having a license plate on your car.
I'm not sure how well that would work w/r/t ATC hand-off and their ability to look up flight plans.
Furthermore, there's the problem of getting the random ID to ATC after the plane has "started up."
Edit: I think it's Opensky that filters their data. Not many planes are filtered but their coverage also isn't as comprehensive as ADSBExchange. For one specific usecase I did find Opensky's API easier to work with
For anyone reading this doing same - you need to fix the ports. FR24 pi image outputs to port 30003. adsb is looking for 30005 and thus fails to find the existing feed
edit it in /etc/default/adsbexchange to align them
In a similar spirit: FR24 should fix their installs and ports.
Install a separate decoder like readsb and drop that FR24 mind control. Then set FR24 craptastic client to read from the decoder if you insist on feeding FR24 ...
https://www.marinetraffic.com/en/ais/home/centerx:-12.0/cent...
A project like Dictator Alert (https://dictatoralert.org/) uses ADS-B Exchange because the authoritarian regimes they're tracking can just pay a commercial site to hide their aircraft—they don't like being tracked.
My Advisory Circular bots (https://skycircl.es/bots/), which tweet in real time whenever they detect police, FBI, military, news or fire aircraft circling, and my "What's Overhead?" Siri shortcut (https://twitter.com/lemonodor/status/1238149529469202433) use ADS-B Exchange because a lot of the most interesting aircraft are the ones that are blocked on commercial trackers.