I think there was dozens, maybe hundreds of different tests.

Some, apparently, were only saline

(for either control groups or simply to generate maximum profit)

Imagine if you controlled the shipping logistics. You could send the hot shots to zones that historically vote one way.

You could even use DNA to genocide a particular subset of race within that zone.

You could test radioactive substances, substances that produce effects in the next generation, nanotech, etc etc etc,

You could use cellphone data and social media posts to individually algorithmically monitor each recipient & use AI to collate all the data. This means only needing limited amounts of people in the know.