Am 19.09.2012 17:22, schrieb Michael Orlitzky:
But practically,
- What do we do with existing mailboxes User1 and user1?
the main question is WHO in the world starting with the same users in different cases?
Who cares, pretend we have supervillains as customers who do everything they can to make my life miserable[1]. It's required by RFC, so not unreasonable for a customer to request. We're not going to turn down a new hosting client because they had John User Sr. and John User Jr. using JUser@example.com and juser@example.com at their old company and we can't do it.
your problem
having "JUser@example.com" and "juser@example.com" as address for two different people is plain stupid and it is really your problem if you think it is a good idea to satisfy stupid whishes