[blagie]

The entire mess isn't with data in databases, but on laptops for offline analysis, in log files, backups, etc.

It's easy enough to have a SQL query to delete a users' data from the production database for real.

It's all the other places the data goes that's a mess, and a robust system of deletion via encryption could work fine in most of those places, at least in the abstract with the proper tooling.