Not all leaks are unauthorized. Organizations often want to put information or misinformation out without taking responsibility for it. The media has paper and airtime to fill, and may or may not be picky about its sources. It is not unusual for an organization to do authorized leaks and try to chase down unauthorized leakers.

I'm not sure how many reporters have done jail time to protect their sources, but I'm sure that more than a few have been threatened with it.