Thank you for your both replies!
My suggestion is not based on boredom or mere whim, but on my personal situation. I have recently been the target of unpleasant phone calls (coming exclusivelly from unknown numbers - that is why I suggested that specific option) of a business or other (much more serious) nature, and the call recording is often the only conclusive material for further (e.g. legal) action.
In this sense, from my point of view, it is a broader (less technical) concept of 'security and privacy' and it is for this reason that I have decided to ask a question about a possible extension of the functionality of call recording.
Thank you for your understanding.