I could never understand why they couldn't just issue everyone with a random candidate number in the exam booking and then post all the results in a oner on the web. With an option you could opt out if you like. It would save the CAA money as well, unless you opt out they will only have to produce 1 bit of paper at the end when you have finished.
Unless you have told someone your number know one will know who you are. The numbers won't be traceable to a school. It will stop the phone lines getting clogged up with questions about when the results are out and then everyone will have access at the same time.
MJ