I did understand the point perfectly. The mechanism was there simply for the good actors to backtrace the data to the matching person, it's purpose was never to

I did understand the point perfectly. The mechanism was there simply for the good actors to backtrace the data to the matching person, it's purpose was never to play a part in making the data more anonymous. If what you meant to say was the more clear statement that adversaries wouldn't need to do that then I'd have agreed with you. Everything else that was mentioned; the strict processes in determining what data could be stored, what it exposed about the user if anything, eliminating as much of the human input as possible and the post processing of the data before it left the measurement lab. These are the steps that achieved anonymity (as far as everyone believed had been achieved).