For Business Guest attendees what information is required in your set up? With GDPR guidelines coming into force in Europe then having the Business Guest email address as an identifier would require permission from the Data Subject eg Business Guest which I am struggling to get my head round how we would implement
Usually when I am implementing clients, the only details I capture for Business Guests, are first name, last name and company. The email address is not a field I normally see. You can configure Concur to match based on certain criteria, I check for duplicate attendees on First name, Last Name AND company.