Interesting. Use is an important factor in design.

My thought devolves to the legal uses of this data - not whether you can capture the data in the first place.

Does one have a legal right to data about your actions (in this case a phone call) that is captured by a governmental entity? Further, can you subpoena the data for legal use? Say you know you are the suspect of a murder investigation and you know the fact that you made a phone call could produce an alibi for you. Lacking that you look pretty guilty and might get injected. Could you subpoena that data for your defense? If you could do it for this purpose, where do you draw the line backwards? Could the database be subpoenaed in a divorce proceeding to better establish through the showing of routine and frequent phone calls that one of the parties was involved in an illicit relationship outside the marriage?