One thing to watch out for when registering. All of the extras (clothing, donations etc.) require you to positively select them if you want them. Except insurance. I don't need the insurance any more than I need it when I ride to work each day. I have my own medical and disability cover, so I read the first line offering insurance and just moved on with the registration process.
However, the check-box for insurance defaults to ticked and you have to untick it if you don't want it. There's no page confirming what you're about to be charged, so the first I knew that I'd bought the insurance was when I saw the invoice after the charge had gone through. It may only be $5.50, but to the insurer (no doubt HBF) it's about $38K of revenue and it annoyed me that I'd been conned like that. I phoned the organisers and they said to email them and they'd refund it.