I've heard of a conspiracy theory about how an alien visit/attack/scare will be seen by many. In reality it will be the US government faking the visit/attack/scare to increase the defense budget. If we are defending against aliens there would be unlimited funds going towards the defense industry. We are cleaning up in the middle east so we need a new "enemy".
I think this is entirely plausible. If it does happen, right now we would be in the "planting the seed" stage.
Edit: I know this sounds batshit crazy but with advanced tech a hoax could be pulled off. I have no idea if this tech is available but there have been many skunk works projects we didn't know about for years like the stealth fighter. Technology is also advancing faster than it ever has in the past.