Exactly. Actually, set aside consent entirely. The problem is NOT "how do we de-anonymize". That is super easy. The problem is "how do we de-anonymize IN A W

Exactly. Actually, set aside consent entirely. The problem is NOT "how do we de-anonymize". That is super easy. The problem is "how do we de-anonymize IN A WAY THAT LEAVES RESULTS OF RELEVANT STATISTICAL TESTS INVARIANT". Much harder. Remove a bunch of probably non-random points and make any logisitic regression on that dataset return the same result within some delta. There are trivial impossibility theorems. Really, really trivial. "Left as freshman exercise and if you can't some up with an example maybe step back and stop talking about this topic" trivial. Now, add back consent. "how do we delete a subset of data that is likely not uniformly distributed with respect to risk variables and also de-anonymize the remaining subset of data.... AGAIN, IN A WAY THAT LEAVES RESULTS OF RELEVANT STATISTICAL TESTS INVARIANT". The position is untenable.