Jim Horton points to a story of a reporter who was canned for accepting gifts. Bribery subverts the very thing that make PR possible, editorial integrity.
There are legitimate ways of buttering up reporters and editors. Write them congratulatory letters when they win something for their reporting. All reporters want readers, use your blog to link to their stories. (This works with industry analysts as well.) Recognize the work of their professional societies and trade groups. These are all legitimate ways flacks can cultivate relationships that do not compromise editorial integrity.