[Bring_Back_Shantz]

Originally Posted by Matata

I've always thought that time travelling humans was one of the better justifications for UFO's. Any civilization advanced enough to time travel, would understand how dangerous that technology would be in the hands of self-destructive monkeys like us.

That's a pretty bold statement.
The same could be said about the atomic bomb, or any number of other advanced technologies.

Just because a civilization is relatively far advanced, doesn't mean they've completely done away with people who would exploit that sort of technology.