Whether a face-to-face encounter is required for a breakup depends on the reason for the breakup. If A splits from B because B has been obviously offensive and fraudulent, the courtesy of a face-to-face explanation is not required. Suppose, for example, that Mr. B has given Ms. A every reason to believe that he is not married, but she learns that he is. B then deserves nothing. In the case to which you refer, the young lady deserves a face-to-face meeting, an apology, and whatever solace can be offered. Probably the general rule is that a party who is seriously aggrieved owes no consideration to the aggrievor.
I am surprised that you did not mention e-mail as a medium for breakups. Isn't there a Web site containing form e-mail letters for breakups?
They're well, thanks.
I hate to start our relations by pointing out little details, but both you and "Lovelocked" missed another major point of Chivalry on the question of opening the door for your loved one. The other point is you don't leave her standing alone on the far side of the car and thus more easily jostled and/or assaulted by the nearest purse snatcher or other criminal element who can often appear quickly and quietly no matter the time of day ... just a point, m'dear.
Thanks for your addition to the reasons for helping your beloved get into the car. Unfortunately, it is a necessary addition. Sentimental Prudence prefers to focus on the romantic side of life, but she cannot deny there is a darker side also.