You can use the information in ways to harass and intimidate even without using it for prosecution; e.g. the FBI threatened to publicize MLK's extramarital affair (which they'd discovered by putting him under surveillance (authorized by the then-Attorney General RFK)) if he didn't give up his civil rights work.
Sounds like we'd all need a broader term than prosecution in addition to clearly defining an actual threat. All documented by the same personalities who are often tasked with finding holes in such statutes.
