by Dream Pod 9
@ Vicente. We only have email addresses that Kickstarter provided. And they have all be emailed invites and reminder invites numerous times over the last several weeks. It could be email spam filters but we have no way of knowing. All we know is that of the 20 unregistered we already have the money from 15 of them from the Kickstarter and no way to send them their Backer rewards unless they register. For the other they are Backers that Kickstarter failed to collect on at the end of the campaign.
Have you tried contacting those backers by email/phone? They may not be reading these updates.