Unreliable and known sources

I was reading a story and this thing came up regarding the known and sometimes unreliable sources that you see on the internet and in the newspaper and I started to think why they use these terms. Why not come out and tell us who the source is otherwise the public is in suspense of how he/she got the news and is it really reliable enough to believe it. Maybe the reporters who are reporting it are not sure themselves if the source is reliable enough or they want to protect their sources or they have not verified it and in order to be the number one or the exclusive one to report a breaking news, they come out with it without putting the name of the source. Ok if the source is reliable we will still want to find out how they did get the news. And how are we going to believe that the source is reliable. Do we have any mechanism in place to know if the sources are reliable and credible enough? I really hate it when these people say that we have received information from reliable sources or some unknown sources that this or that really actually happened? I can understand the secrecy but until I can see where the source of the information is coming I remain skeptical. And until the sources are revealed there should not be any rush to come out with a story which does not credit the sources. If we have waited long enough we can wait for more to find out the story with credits