You could also turn your cell off/on as needed. Sure you can be "seen" when it's on, but when off, it's my understanding you can't.
What you could do is put them in a faraday cage if you wanted.
It’s less clear what is the “art of the possible” vs. practical for people who aren’t actively under surveillance.
There are also conspiracy theories that claim the last 10% of battery is reserved for tracking, so that when your phone says its out of battery and wont turn on, it still has plenty of power left to ping tracking data say once per hour or something. I dont push those theories, but judging by what Snowden released all those years ago I wouldnt be surprised.
I started out doing this for a couple years before abandoning mine.
Set it as a local proxy to channel all network access through it and you can selectively block any app from accessing any network, or isolate it.
But IF its possible for law enforcement to ping your phone when its on standby, dont you think its possible that it can be pinged whilst on airplane mode too?
If you are using it on wifi its game over anyway, hard internet connections are easy to track by law enforcement via ip and ISP. Even if you use a VPN your device is still connected to the wifi and can be pinged.
Not sure why people here are thinking they are more clever than than the smartphone makers.
We do not need to wonder, because this is a physics problem and we have science. Radio waves are easy to measure. There have been plenty of experiments with putting phones in faraday chambers with SDRs proving a phone in airplane mode does not emit any cellular frequencies.
You could prove this yourself with cheap home equipment if you wished.
But also, implementing airplane mode that did not actually disable the baseband modem would be an outright violation of FCC law that would be noticed by curious members of the public if this was widespread.
That said a specific targeted device with backdoored software can just make the airplane mode button do nothing, to your point, so physical switches for the baseband are always best, though few devices support them.
If someone has the motivation to backdoor devices they can do the same with physical switches (that will still talk to software regardless). If anything adding a switch that does nothing is easier.