[dainbramaged]

Agreed. Otherwise, why would they be so sneaky?
Maybe they have something like a prime directive, non-interference rule similar to science fiction speculation.
A good friend had a close encounter with four foot tall bipedal creatures in Alaska, around 1968. He was 16 at the time and was so frightened he ran through the front door of his parent's home, destroying it. He was so shook up they reported it to the cops who took photos of the footprints left behind by the "visitors". It even made the local paper and he was teased about for years afterward.
He will retell the story after prodding, but while doing so chokes up, starts sweating profusely and stammering. He also drew a sketch of the critters, which resemble the greys of Roswell fame.

[RoosterRedux]

Yep.

From having read the John Mack accounts of abductees, I'm not sure these said aliens aren't interfering.

Abductees are deeply traumatized by their experiences.