It might make more sense to split this into two issues. However, checkin often involves picking up your badge.
It would be great to help streamline this process.
Common pain points for the checkin process are finding the right badge for the right person, and recording that they attended.
One way to streamline marking folks as attended would be to provide a barcode that corresponds to their signup, which is actually an encoded link that, when followed by a checkin admin, goes directly to a "Do you really want to check in [user-name]?" screen?.
Since smartphones are abundant and most major smartphones support barcode scanning, folks wouldn't have to worry about barcode scanning equipment.