The unique email constraint determines whether constituents can register with an email address that is already in the system. However, because this can sometimes be a problem for calendar events, personal fundraising, and TeamRaiser there are separate settings that will override the site wide setting for each module respectively. By default, duplicate email addresses are allowed for calendar registrations, TeamRaisers, and Personal Fundraising but this setting can be changed. Contact support to have the override turned off. Please note that this can cause problems in the situation where family members register each other for an event who don't have their own email address.

Note: You may also see an admin record with an email matching a constituent record. When you go to a constituent record and click the link to "Create as Admin", a duplicate admin record will be created with the same email address as the constituent record. These records will not show up in the duplicate management tool, as they are allowed in the system so that admins may have a separate constituent record to perform constituent functions.