Don't be lazy. If you think of something that you could do in order to be 100% sure of something, in most cases it's worth doing. There are a ton of stories out there that don't get covered just because nobody bothered to do a little legwork.
There's a world of difference between sitting on a story you dug up about corruption in City Hall and an embargo for news that you wouldn't otherwise have. I also don't think that making publishers mad is necessarily a good litmus test for journal...
If press releases are all you're looking for, sign up on each publisher's investor relations site for news releases. Find some RSS feeds to subscribe to also. If you want even more press releases, try PR Newswire and business wire. If you mean res...