DVR makes this MUCH more difficult because fast-forward/rewind vastly increases the number of datasets you need to compare against. Also, while in theory you could identify a DVD, the selection of possible DVDs is so great and the amount of noise in the measurements is such that you're never in practice going to be able to identify someone's watched content reliably.

Welcome to my world. I write software for computing TV ratings, including for DVR and VOD use, and capable of being used for DVDs. It already exists.

I'll quote The Register on why it is sad that you don't think there is anything wrong in this:

Once, we did understand. Twenty-five years ago, Independent science correspondent Steve Connor and I wrote a tome about Britain's Databanks and the effect of growing data processing on civil society. Steve had located Britain's first ever vehicle Automatic Number Plate Recognition (ANPR) device, a washing-machine-sized contraption planted on a motorway bridge near St Albans. It heralded the potentially tyrannical ultimate development of a nationwide movement surveillance. We both reached for and proclaimed words from early reviews of data protection laws that had warned that new sensors and new software such as free text retrieval (FTR) raised "new dimensions of unease". A quarter-century on, these words are all but unsayable. The thoughts no longer fit the world.

a growing cadre of Christian scholars who say they want their faith to come into the 21st century

Christianity has already done that. The problem is not Christians, but fundamentalist Christians. I'm an aetheist, but if I were a Christian I would be enraged at the way that fundamentalist Chrisitains identify their particular sect as Christianity in toto, labelling everyone else who also calls themselves a Christian as not Christian.