check-in functionality

I was wondering if, apart from the options of waiting list, attend or not attend, an admin of an event could use the check-in functionality as Eventbrite and other event managers do. Now I just use JEM as a guest-list and if would be great if I could actually strike off the people on the guest-list who really showed up, as in check-them in on site. After the event I could then mail those who really attended and not just those who have set themselves to attending.

Looking forward to hearing if such functionality exists can easily be coded or might be released in a newer version soon?

The attendee record (registers table) will need to be extended to have another field (checked-in). Model and view changed to allow administrator (back end) and event organiser (front end) to check-in and check-out attendees. Mailing plugin / settings extended to allow send e-mail to checked-in users only.
Probably, needs to be looked as a part of complete event handling re-design, including payment processing and ticketing.
Any comments from JEM developers?