They do acknowledge potential issues: "these observations are either fabricated or seriously in error, or that these craft exhibit technology far more advanced than any known craft on Earth."

And their selection process: "These encounters were selected from a subset of cases for which there were multiple professional witnesses observing the craft in multiple modalities (including sight, radar, infrared imaging, etc.)."

Some of the cases have multiple witnesses and video of the objects. You can look at it yourself.