[otrs] best way to force customer's username equal to email address

Hi, All, I want to force all client's usernames to be their email address. I know it is possible to do in OTRS, but before I dig in, I wanted to check with all of your to see if any one else had undertaken this & how they found was the best way to go. We could customize the CustomerFrontEnd, we could fire off a PreModule, we could do something inside SQL, we could run a cronjob to check it (& change it) nightly, we could do a lot of things, but, again, I wanted to see what others had done to accomplish this. I think this might be a nicety that the entire community could use. Thanks so much. Jason Sjöbeck