It seems telling that as camera and detection equipment has gotten better, presumed "alien" UFO elusiveness has advanced precisely in lockstep: not too much to stop being detected altogether, but not so little as to be definitively identifiable.
The weather balloon that would not be detected at all before can now be detected as a UFO. As the range of sensors expands the LIV probably gets bigger too just because the radius is larger. The more sensitive and numerous the sensors, the more false positives you get.