UFOs exist. As in the actual technical term. Every nation that puts planes in the air has observed things that can't be identified for generations now. Many of have been debunked. Many have not. Now whether what WE think of UFOs is of course highly debatable. Our current perception fueled by Hollywood and sci do writers I mean.
Hypothetical time. Let's say UFOs exist, there is absolute proof and lots of it and the government has it. You are the one who says whether or not the info gets released. Do you do it?
Remember, this is not bacteria on Mars we are talking about. But advanced organisms with the power of space flight.
My answer? I don't know for sure. But right now I lean heavily towards no. At least not without a LOT of prep work beforehand. I think I would work towards that goal but just one day calling a press conference and be like, "oh by the way, here is a alien spaceship", while pointing at it. No way in hell. Truly imagine what that kind of news would do to the world. Actually in semi serious mode now. We go to war if we think certain resources might be mishandled. Can you imagine what news of actual life, ostensibly more advanced than us, would do to the world's.....everything?
Its why I've never scoffed at "gubment cover-ups" when it comes to this subject. Because I am fairly certain I'd do the same thing. At least initially.