Highly visible shiny UFOs, really?
Your a civilization that's at least 8 to 10,000 years older than Earth's in order to get from their planet to this planet. Our jet fighters are painted to make them harder to spot in the sky, it's called camouflage, correct? And you want to tell me that a civilization that is barely 2000 years old has better technology than somebody from another world? The question isn't whether UFOs exist, the question is which planet are they from, ours or thier's? Your visiting an unknown world with a civilization that is capable of shooting you out of the sky and you have a choice between a bright shiny disc that everybody can see and a UFO that is at least camouflaged, if not cloaked, which one do you choose to visit Earth in? Now if you're an earth scientist who has stolen UFO technology your not likely to be concerned with what color it's painted, and more likely concerned with whether or not you can even get it to fly.