There is far more checking, corroborating, debating, arguing, vetting than any viewer could possibly know.
When Houston Chronicle reporters want to use information from an unnamed source in a news story, they have to jump through a few hoops first.
A senior editor has to approve it, and know who the source is. A single unnamed source is rarely enough to go ahead with a story - there must be two sources with the same firsthand knowledge. And one of a handful of top editors must sign off on its use before publication.