The core of this criminal business is to give back your valuable data

Impetus

https://krebsonsecurity.com/2019/08/insynq-ransom-attack-began-with-phishing-email/

Bacchus

Hard to take that ransom note seriously.

Wonder has anyone considered that the three files they open for free will likely also be considered "highly valuable files" by the cyber-criminals (I mean, if you're going to get three files back straightaway it's quite possible they'll be important ones). Therefore it's also quite likely that the cyber-criminals will likely open those files for a little look... could be a good opportunity to bite them back

Impetus

Recorded Future and Security Weekly netcasts often have guys representing IT security companies whose business model is to install 'sexy' files on computer networks (eg files named executive_payroll.xlsx, passwords.txt and similar).

Anybody opening one of these files triggers an alert system - 'possible hacking in operation', IP lockout, or diversion to a 'disney world' server of stuff to make the hacker hang around and play etc. Obviously if s/he is in North Korea, there isn't much that can be done to trace them.

https://securityweekly.com/tag/podcast/

https://www.recordedfuture.com/resources/podcast/