My vets more or less said the same that the treatment and cure are the same and the treatment is effective. He said something like "you wouldnt take antibiotics 'just in case' would you?"
But on Facebook, it's been said that rabbits, by nature, hide their symptoms when they're ill. It's a survival mechanism as in the wild if an animal can sense that a rabbit is ill it was go for that one first as it's the weakest. So therefore by the time we start to notice symptoms it's usually too late to treat them.