Data privacy is an engineering problem - and currently there aren't any really good open-source tools to 'solve' data privacy - it's really up to the application developer to make sure they don't mess up. If the organisations is sufficiently large there is a CISO to ensure the correct processes are in place so that this sort of thing does not happen.
I think in an ideal world data privacy should be addressed by open-source software enabling software developers to easily express data privacy as code and version control it and review it much like we do with our infrastructure.
There is an product [0] which is currently in Alpha aimed at doing this. (Full disclosure I am one of the core devs) We don't support S3 buckets yet - but it's on the roadmap.