Chaos in Sydney airport

I went to Brisbane from Sydney tonight. There were a long queue for check-in tonight. Orginally,   I guess there are some IT system problems, because Virgin Blue will charge for every luggages, therefore, they need to change the system for the new measurement and only a few counters opened. I am an IT people, I clear know about any changes will be very high risk for bugs/system error. But after I was on flight, they said that is because of bad weather.