That sounds likely Pete.

Another idea;

Now that most people have a camera available everywhere, where are the remarkable ufos?   Where are the multiple perspective photos?
By Pete's deduction perspective the ufos would know of their mass detection and avoid this deliberately.
It is easier to assume the phenomena is not as we may have thought.
Either the universe has expanded to non visitation distances or they did not exist at all which is what I SAID 35 YEARS AGO as a person on a UFU radio panel.

I'm hoping I am wrong.

If there is a cost risk decision to be made by aliens we may be decidedly too dangerous.