When a volunteer registers for your event using the same email address as someone else, we indicate this relationship to you by linking their profiles together. This simply means that the email address is shared by one or more individuals.
Although they share an email address, these linked volunteers are treated as distinct (separate) sign-ups within the system. For example, an event-wide communication broadcast would actually send multiple emails to the shared email address. Each message would populate with the proper first names, shifts, and unique profile links for the every linked volunteer.
The downside to this approach is when "Andrew" registers once as "Andrew" and later as "Andy". Our system treats that as two people, and "Andy" will end up being linked to Andrew. We have a tool to find and merge linked volunteers who are actually the same person.