@ Chris: Yes, we use cards that are 1/4 page. They have driver name, car, class, and number, and emergency contact preprinted if it's a preregister, or they are filled out manually for a walkup. Then there are initial boxes for tech and payment, and check boxes for run group and workstation, which are assigned by the cashier station after the car passes tech and the driver returns to pay.
These cards are then collected so we have manual backup of attendees in case of system failure. While the driver's meeting is going on, one of the registrars takes 10 minutes and checks everybody in using the Driver Checkin screen.
It's not just a duplication issue, it's data hygiene in general. With drivers making their own accounts, we don't have control over that data. So not only is spelling and capitalization an issue ;) but one guy may say he has a subaru sti and one guy may say he has a Subaru Impreza WRX STi. A number of my volunteers probably wouldn't know that's the same car. Plus, it looks roachy when we publish the results.
Brandywine Motorsport Club Autocross Chair
AXti.me user since 02 April 2015