Yes, exactly. It was done that way to isolate common attributes of encounters which did not have circulated in the media or the general UFO lore yet. J. Allen

Yes, exactly. It was done that way to isolate common attributes of encounters which did not have circulated in the media or the general UFO lore yet. J. Allen Hynek, the lead of project Blue Book, encountered the contamination issue very early in his works, and a huge amount of his research is to this day unpublished to prevent that from happening. As you might notice, this is the complete opposite of how scientific inquiry works. As Vallée concluded, this is an intelligence problem before a scientific one. From that standing, we can understand an UFO encounter as a cybernetic system, not just a physical event. Which leads to consider the UFO phenomenon as informational phenomenon with informational effects on cultures, thoughts and ideas. A lot of Vallée's work is exploring this, which is really fascinating.