I was about to suggest this, because anonymised data is often not-so-anonymous in aggregate. AT&T's recent disclosure of selling this information to bounty hunt

I was about to suggest this, because anonymised data is often not-so-anonymous in aggregate. AT&T's recent disclosure of selling this information to bounty hunters[0] shows that sharing across companies isn't always done with the end goal of user privacy. Examples of over sharing can set precedents in court cases showing that such sensitive data can be treated as a liability rather than an appreciating asset in the wrong hands. [0] https://www.eff.org/press/releases/eff-sues-att-data-aggregators-giving-bounty-hunters-and-other-third-parties-access https://www.eff.org/press/releases/eff-sues-att-data-aggrega...