I now understand the point heartybob was making, and agree that I slightly misunderstood it. However...

Well, I usually receive about ten useless emails from BA for each flight that I take. On my last flight LHR-JFK, I received three identical emails on the same day to tell me online check-in was open. I receive reminders to use MMB at various intervals before the flight, often two or three duplicates at a time, especially it seems if the flight has been MFU'd. I receive emails to let me know that I've changed my seat, supplied API, or checked in - facts which I invariably know. Compared with all these, an email to tell me that my ticket has been cancelled by someone else would be vastly more useful.