Because a unique email is required for login, you need to supply an email address for each guest that you want to login to the pregame site. While the email address does not have to be their real email address, it is preferred so they can recover their password if they need to. If you assign the same email address to multiple guests, they will all have access to the others host and guest information. You definitely don't want to do this with the host account, so be sure not to assign your host account email to any of the guests assignments unless the host will be assigned to that guest. For security reasons, the host can not view or update the guest passwords.
So if you don't have an email for a guest you can simple make one up, for instance. If you are throwing a birthday party for susie, you might label them:
- Email: firstname.lastname@example.org