In the realm of Avalon, Camelot or whistle-blowing and disclosure in general we meet a lot of people keen to tell their message. Weather they tell the truth or not is a difficult task ( and possibly the reason you are here ). What can be established fast and objectively however is what methods they have used in obtaining their information.
Some use the scientific method ( i.e. Richard Dolan ): everything they say is backed up by a paper or book they have written. All the information they have used in their book or paper can be traced back to the source. All sources have have been documented by them. In mainstream science a paper is normally peer-reviewed. In the case of a publication about UFO's for example it is often difficult to find peer-reviewers. They take part in forums, answer questions, accept crticism.
Some use the journalistic method. ( i.e. Linda Moulton Howe ): everything they say is backed up by an article they have written. All information used can be traced back to the source. A journalist however can quote from information to a source known to him/her but which he will not reveal. The reason for this is always explained. - The trustworthiness of the reporter is key in judging information gathered via this method. They answer questions but never reveal their secret sources.
Some use the anecdotal method. ( i.e. Bob Dean ) who ( often in detail ) tell about their story but without delivering any proof whatsoever. The pleasure is in the listening not as much in the quality of the information. They are reluctant to answering questions and accept no criticism. Some attribute their 'story telling' to a narcistic personality disorder.
Some use the prophetic method ( i.e. David Icke ). They present themselves as -the source-. There is no need to trace back any information, because they -know everything-. When David Icke talks, he lectures, he communicates the Truth. He attributes his qualities to a transformation he had in Peru when some sort of God entered his body and implanted total knowledge into him. ( Or something like that anyway. )
What is also important is the money they ask you in exchange for the so called disclosure. What was the value of that information? Was it worth it?
The truth -is- out there. I wish you lots of wisdom in finding it.