Because
they are trying not to freak us the fuck out. When the human race wakes up and realises we aren't God's creation, but the product of some alien species' experiment, we may not take it too lightly.

Soooooo, the aliens visit us, do all the things they want to do, clinically observe us at will, just like the scientific subjects we are, and there's absolutely nothing we can do about it.
Now, to stop us running around in a panic and society breaking down, the aliens play a little game where they fly about in brightly lit craft, juuuuust out of reach and unable to be proven. That's why with all their technology they always seem to be mending their ships or collecting soil samples in clearings in woods, before being "surprised", jumping back in and zooming off. If they can travel across the universe, they can surely tell that Billy Bob is approaching and leave before he spots them? Unless they want us to get a glimpse, it stops us looking elsewhere, other more overt places for them............


Anyway, I didn't come up with this theory, nor do I necessarily subscribe to it (in fact I don't really give a toss, I have enough to worry about without aliens being involved)


Read the Krill Papers and decide for yourself (composed by OH1 Krill, an allegedly real-life gen-you-wine alien), if nothing else it's a good read and doesn't quite follow the usual paths of UFO/alien theories, which actually makes it that bit more plausible.
(Rsoles, Mon 7 Jul 2008, 22:41, Reply)