A scenario like that would never be allowed to happen
First of all we are primitives. And even our weapons and methods of delivery are primitive to any star-faring nation out there that has managed to get all the way over to us.
As evidenced by previous contacts, they have the power to disable ANY of our electronics upon whim, and vaporize us if need be.
And we certainly don't have the balls to take on these highly evolved time travellers with Super Powers. Perhaps we are getting ready to have a lesson? I hope I live to see it.