Your post seems to be based on the premise that there is a government-level conspiracy.
Anyway, if they did I would pay massive attention, then I would get worried: no good can come from first-contact, we're still a very primitive civilization compared to what we could be, and we don't need external influences that would just mess things up.
And then there are theological issues to contend with.
Why are you asking this all of a sudden?
Well, I ask this because I am certain that it'll happen very soon, between now and 1-3 years from now. And yes, I'm aware that it sounds very religious because I have no proof what so ever to back it up. It's just a gut feeling. So I was curious how people would react on such an event.
From the looks of the replies here, we won't have much of a panic. hehhe... although, we are probably less xenophobic in the tech community than "others" since we are "hopefully" more science related people.