A Japanese company is selling a school ID card system used to automatically take attendance and notify parents when their child arrived at school.
This is something I've thought of myself, and it's a great idea, except that technology is still too expensive to make it both affordable and practical. Without authentication, it's a real easy system to beat--give your card to a friend (or an acquaintance looking to make a few bucks) who plans to show up and get them to swipe it. It becomes even easier if it's a proximity card or RFID. I can't find out any details, as NAJ's web site is entirely in Japanese. PINs would be bad authentication, since you could write it on the card. Unlike ATM cards, this is a case where biometrics would be a good solution. You can't pass the authentication method to your accomplice, the bar is too high for students to create biometric forgeries, and there's no incentive for a thief to cut off your body parts.