Possible that opting out --
-- may become somewhat punishable.
An acquaintance of mine is disabled, and was trying to find affordable housing. The market here is very tight. Being quite skint, he had always paid in cash or checks for everything; no plastic. Several property management companies turned down his applications to rent because he has no credit history.
Future: "Terribly sorry, we can't sell you a car. You've insufficient data in the GoogBook registry for us to evaluate." Or "Membership in our discount store is denied; insufficient customer data in GoogBook."
Who knows, though. Any coercive commercial tactic can be an opening for startups emphasizing non-coercion, non-tracking, non-spying.