The intention to prevent child sexual abuse material is indeed laudable. But the "solution" is not. For those wondering what's wrong with this, two hard-earned rights in a democracy go for a toss here:

    1. The law presumes we are all innocent until proven guilty.
    2. We have the right against self-incrimination.

Pervasive surveillance like this starts with the presumption that we are all guilty of something ("if you are innocent, why are you scared of such surveillance?"). The right against self-incrimination is linked to the first doctrine because compelling an accused to testify transfers the burden of proving innocence to the accused, instead of requiring the government to prove his guilt.