Not so sure about the alien contact thing; though it has been popular the last 30 years or so. I see Stephen Hawking and Elon Musk got on the band wagon with some wanna be alien contact project last year.
The way I look at it is inviting a bunch of highly advanced (as in interstellar travel advanced) aliens you've never met, and know nothing about to your crib (assuming they show up, of course) is the tech equivalent of online dating at serialkillers.com. NOT gonna end well whether they're friendly or "the other kind".
Even if they're friendly...............you may count on every government that possibly can, and perhaps even some super rich meddlers; will be busting their asses trying to glom onto some alien tech for whatever their own reasons are. ANY sudden transfer of advanced tech is highly likely to devastate entire swaths of national/international economies as the old tech is suddenly needless/useless. That's a whole bunch of social and political unrest, and all the pleasant shit that goes with it. Say Mr. Spock and his Vulcan Bros suddenly show up
; flip us the peace sign and give us the transporter platform/beam? Voila!!! Depending on the rapidity it's brought into service with.........................there goes billions in transportation industry economy, cars, trucks, railroads, people who build/maintain roads, road making machinery, car tires, you get the drift. One core tech goes down the drain, then the ripples take effect. Whole economy is ****** up..............that's when the unrest starts. Thanks Mr. Spock! Or course the people raking in the billions in new wealth and influence won't mind so much....................surely they'll look out for the rest of us?
And what government wouldn't do ANYTHING to get it's hands on some shiny new shit to kill other people with? Now it's really fun; as the entire world power structure is radically shifted even more quickly than in the above fairly benign scenario. Gravity polarization for extremely manuverable and fast transatmospheric aircraft anyone? How about a really small power pack/source to make those directed energy, and electromagnetic party favors small and feasible enough to fit on something smaller than a Zumwalt class destroyer? **** yea!! I'll take three!!
Take that you fill in the blank with most hated group
Bbbbaaahhhh!!!!! I worry too much.........................what could possibly go wrong?