Stupid Qustion time

I was hearing how Rogers is changing the email address' for all of it's customers. That's fine. But all users have to do the changes themselves on a website. Time for my stupid quesiton: Why can't the change be done automatically with the users only having to notify people of the change? I ask since this is what was done at my old university. So one group did it, and the other did not. Can anyone tell me?