Sign people in as they arrive, correct their details, add walk-up entries, and send each person to tagging.
The Registration Desk station is for whoever is signing people in. It works best on a laptop.
Somebody turned up without entering? Add walk-up at the desk: choose the class and take their details, which takes about a minute. It is added without payment and recorded as paid, so take the money the way your club normally does.
Pair a tagging device with the desk and everyone you sign in appears on it straight away, so the person tagging does not have to look them up.
The desk cannot take a card payment, see any other event, or delete an entry.