I've always thought this will be one of their big tricks they've got waiting in the wings.
Originally called "Project Blue Beam" in FOIA documents released in the 90's. A fake alien attack could be used to mobilize the population quickly for an unpopular war. They'd be on the ground in the latest third world country fighting before they realized there were no aliens. You're laughing and you don't know, the government discussed this seriously. A lot of people might suggest they are already doing it with ISIS in the Middle East.
I think if there were ever a serious chance of a lot of them going to jail, suddenly the planet would be under alien attack. The technology exists today to fake a lot of big things in front of people. If done at night you can really make it look like a football field sized UFO is hovering over a city. Scattered reports of them on the ground with some guys running around with rubber masks on, add some air raid sirens and the panic would be apocalyptic worldwide. It wouldn't take much and would be an enormously effective diversion. People would do whatever the government told them to do. You know it's true, I've been in minor events like this and you would not believe how quickly the average person completely loses it. Their critical faculty, barely functioning in the best of times, shuts down completely once they are scared.