This does sound like the standard UFOlogist "maths without numbers" argument - "Well sure, we can discount an unknown number of hoaxes and an unknown number of misidentifications of aircraft and natural phenomena, but that still leaves an unknown number of sightings which are something else." This quickly translates to, "If there are that many sightings, surely some of them must be of extraterrestrial origin?"

To which of course the answer is a simple "No."