Kinda both. Somebody had to write those complaints to the NKVD and participate in those meetings demanding to put down the traitors like rabid dogs. And if you

Kinda both. Somebody had to write those complaints to the NKVD and participate in those meetings demanding to put down the traitors like rabid dogs. And if you didn't participate enthusiastically enough, be sure the NKVD would hear about it the next day, from multiple sources (and also would hear about everyone who didn't write). It was a system where participation wasn't optional.