The burden of proof is on those making the claims, not those who find the data dubious. If there are investigators who are convinced that craft from other worlds are buzzing ours, then they should present the best evidence they have, and not resort to explanations that appeal to conspiratorial cover-ups or the failure of others to be open to the idea. The UFO advocates are asking us to believe something very important. After all, there could hardly be any discovery more dramatic than visitors from other worlds. If they could prove that the aliens are here, I would be as awestruck as anyone. But I still await a compelling Exhibit A.