There are very strict federal and state laws around who can or cannot record phone calls and how admissible they are in court.
If anyone knows how to convince Android to change his mind, I'm "all ears", as they say.
* Android is obviously masculine gender, but I've named my phone "Kathryn". Hmm...
IAAL, not providing legal advice etc.
But pushing this absurdity a bit further, what exactly makes it a voice call instead of a text chat? Either way, there are bits moving over wires.
Let's make a new "voice codec" that can trivially encode and decode to text (like Speak'n'spell phonemes) so that the bits on the wire technically represent some "audio data", but with much less overhead than the usual TTS.