Where did you get that impression from? The WWDC keynote mentioned recording calls on iPhone (with transcription) and said that the other end would be notified when you start recording.
Oh really? Unfortunately i didn’t see the keynote this time and i didn’t see this in any online summaries. Didn’t expect they’d do it this time! Ive been asking for it in prev years. But does it record audio? This is good if you get to keep audio!
They just announced this:
Record and transcribe a live call directly from the Phone app.21 You can also search call history more easily, dial smarter, and switch SIM cards seamlessly.
they actually showed the option to do that with a full AI (apple intelligence of course) summary made on device.