If this is a concern (i.e. if the fact of a person's membership would be considered sensitive information), one solution is to process the registration normally from the user's perspective on the registration page, but send a different e-mail out that explains that an account already exists/gives details on resetting the existing account (or replacing it if applicable) rather than a confirmation e-mail to verify the address.

Should you let users know if an email has been taken during registration validation?
I've been asked by a client if it is possible to prepare our product for deployment via SSCM. Currently we produce an msi installer; is that what SCCM would need or do we need to do something to the msi package to make it SCCM friendly?
