You can't believe everything you hear, as someone once said, but apparently that unidentified someone was wrong for once, they are now saying, because information of any kind from anonymous sources is said to be completely reliable.
The word is that generic advice on important matters, news of improbable scientific breakthroughs and discoveries, dubious fiats on the subject of maintaining optimum bodily health -- essentially any amorphously authoritative declaration whatsoever -- can be treated as gospel by the intended recipient, no question about it. Furthermore, they know for a fact that no matter how farfetched such information may seem, and regardless of the reliability of the individual citing the anonymous source, the proffered information is nevertheless dependable -- guaranteed.
They say that, as events have shown, we can rest assured the information we're getting is accurate, and that the supposed importance of identifying sources is just an old wives' tale. The cognoscenti also insist that it's only common sense to accept on faith the veracity of unspecified sources, despite what you may have heard to the contrary. Therefore, as to whether or not anonymous sources know whereof they speak, the record speaks for itself, as they say, and believe me, they ought to know.