Great article. I especially like the diplomacy / courtesy example.
I've found in many companies that IT doesn't get notified when someone leaves. Indeed, in my current company, sometimes HR isn't notified.
The best setup I've seen tied logins, emails, etc to HR records. HR would update their records. That data controlled email addresses, logins, etc. "If you don't get a paycheck, you don't get an account". The 1st problem we had was getting some HR personnel to not use the caps lock key all the time.