There's an app people can use to take photographs of hotel rooms. You take one photo from the doorway, and one of the bed.

This gets uploaded to a database for law enforcement to use to find locations when they get images of child sexual abuse that happens in hotels.

https://news.ycombinator.com/item?id=12058357

And there's also this article about one such takeover of a site that distributed images of child sexual abuse: https://news.ycombinator.com/item?id=12084471