In article <1141987417.620138.308840@z34g2000cwc.googlegroups.com>, 
ianparker2@gmail.com says...

2 and 3 certainly exist.

1 can't. The fundamental reason is that an advanced civilzation would
go about observing us in a very different way.

Oh sure, you can predict exactly how an advanced civilization would
behave, as to their edicts and rules they live by....
Only that we are not talking about one ET species/race.

It is arguable what those edicts and rules may be.
For instance it is reasonable to assume that most advanced civilisations
would behave in a certain way, generally, then again there can be other
advanced civilisations that would act differently, with less moral
motives in mind, or with none. Who are less advanced, but may have
superior technology to ours.

Do not let your own mind (being your current values and reasoning only
at this time in your life) stop you from seeing the truth.
The truth contains the information that is out there - but we see our
own truth (understanding) in all of that.

And in trying to get to the truth, you have to realise what is exactly
truthful? And what isn't...
In that governments (particularly the US) have been lying to us, about
UFOs. There must be a body of information gathered about UFOs by now,
if you go by the number of indisputable sightings and crashes.
Someone has been gathering up all this intelligence and data.

You can work out who has been lying - by the body of evidence, and
what the official story/response has been.
You use the same method to determine what other big story (stories)
that have been withheld from the public, when the evidence points
to a different story from the official version -
ie. JFK assassination, NASA moonlandings a hoax?, TWA800 brought
down by a missile, 9-11 perpertrated not by Bin Laden, etc etc.
The evidence/information remains the same, eyewitness testimonies
remain the same. The official story gets to be repeated time and time
again, in trying to persuade the public to accept this official story,
attempting to rewrite history.
Religion has used this method, to force the public to accept it's
official version of events of that religion - whether it be Jewish,
Christian or Muslim. Repeat it often enough and long enough, and the
public has no choice but to believe the official version - even though
it remains nonsense and unbelievable.

You have to use reason and logic to sort out which is more likely to
be the truth, and go with the information/evidence - and the most likely
story to colloborate that evidence. In other words, to use very
basic detective work, to work out who is killing the truth, and who gets
the benefit from that acceptance, explaining the motive.

Terrestrial UFOs do exist. You need to look at secret Nazi projects
during WWII.
One type is already recognised, no doubt others
do fall into this category too.

Harvey