Well that's it isn't it. Supply good information you can charge more and get asked again. Provide poor information you get less and you're not believed in future. Journos work in football consists of being told information rather than any investigative work. It's judgement. All journos are going to be fed a constant stream of bollocks. The fact there's no repercussions for printing bollocks, Journos appear to just print everything they've heard.
Add to that there's quite clearly 'deals' between journos and agents in regards to releasing information, whether it be false but want to generate a move or a new contract of what ever. It makes it even murkier water. You just don't know what to believe anymore.