RE: Scream into the void! Space communications
The problem is free choice.
If we, the human race, decide that aliens aren't real, they aren't. We will never interact with them.
However, it looks like we have decided to enter the galactic stage, and so, expect actual alien contact soon. Within the next decade.
Aliens have already made contact in many, many ways.
And, it is in my estimation, that sending out radio waves is just something to appease the masses.
Govern-cements already know about aliens flying about. Radar stations pick them up all the time. If you get a pair of (correct type) night vision goggles, you can watch them flying about. If you live high in the Andes, you can watch them with your naked eyes every clear night. So, i am pretty sure, that they know that they don't use radio waves to communicate.
What we, as a race need to do is get over our warring tendencies. We have to learn, then make one in ourselves, that war is never the answer.
The idea of an alien race coming to conquer another planet is ludicrous. Just this idea means they we don't know what life is. That we don't know what a planet is.
As an example, people do not lose bone / muscle mass due to lack of gravity in orbit. They are lost because they are not in the earth's magnetic field. So, we do not survive for long on other planets. Conquering is stupid, idiotic, doesn't gain anything, and life is too precious to be going around doing something so stupid.
However, this is not to say that all alien races are nice.
True, whenever we speak about future under these terms, we do so under the limitations of our current technology and physics¡ knowledge. Lightspeed is our limit (as far as we know), and we haven't been able to even reach that.
The rest, is suppositions fed by people spreading "news" that have no real hard evidence behind.
Your reference to ball lightning (how casual, I lived in the Andes for several years) being confused as "alien vehicles" is a common misconception. Some believe they are "la luz mala" https://es.wikipedia.org/wiki/Luz_mala
Others, aliens.
It is just lightning, until proven differently.
It is also true that we are a bellicose civilization, and that we've no way of knowing if any "visitors" didn't actually evolve over a warfare-based culture and expansion. I always considered that we need to be very cautious whenever we "call to the stars"... We never know what we could we be inviting into our primitive civilization.
In case we contact a Civ that is rather equal in technology to us we've nothing to worry about. But, if they're more advanced... we may be fucked!
This is why i started off with saying, its free choice.
Seeing is not believing. Believing is seeing.
There are so many alien encounter / sighting stories that to believe it is all fake is really large leap.
Further, there is intelligent life on earth that we haven't made contact with.
Run that through your mind.
Entire races living in parallel with us.
It will be a very interesting future now that we have decided to open up to contact.
Going forward, the tide will turn from mostly doubters, to few doubters.
Too esoteric for my taste.