Google has threatened to remove sites that do not clearly label ads as ads from Google News.  Here's what the Google News blog said, " If a site mixes news content with affiliate, promotional, advertorial, or marketing materials (for your company or another party), we strongly recommend that you separate non-news content on a different host or directory, block it from being crawled with robots.txt, or create a Google News Sitemap for your news articles only. Otherwise, if we learn of promotional content mixed with news content, we may exclude your entire publication from Google News."

Many sites use sponsored content in the form of news stories and other methods.  In the future clear and distinct labels are necessary if one does not want to be banned from Google News.