[AndrewDavis]

This is something I've never understood. If consent is remaining on the line after a message "this call may be recorded (for training and quality purposes)", the simple answer is in places where you have to have consent have the phone send a similar message.

[lazide]

No need to send - if there is no expectation of privacy because one of the parties is recording, then everyone can.

(Check applicable state law, but it has been true everywhere I am aware of)