As far as I'm concerned she is a pretty respected Chief Justice who probably knows one heck of a lot more about the law than everyone posting here. 

I think her point is that the justice system works in a particular way and even if in your heart-of-hearts "know" someone is guilty, courts demand a higher level of proof. An' if you don't got it, the courts aren't going to decide in your favour. 

And if you want to change that to make prosecuting a specific crime easier (e.g. 'Guilty until proven innocent'), the legal system will end up working in quite a different way.