It is the day of a sold-out event, and everything seems to be running smoothly until you find out that there w?

It is the day of a sold-out event, and everything seems to be running smoothly until you find out that there was a typo on the website that advertised $10 day of registration. There are about 1000 people happily waiting to cash in. What are the logistical effects of such a situation, and how do you deal with them?