For years the Berlin Wall and machine gun nests kept East Germans out of West Germany. Then the Soviet Union fell.
For years the U.S. border patrol has failed to keep Mexican and other South American immigrants from illegally entering the U.S.
Now Britain is unable to keep migrants from going through the channel tunnel from France. Are conditions really that much better in Britain?
There are two answers. (a) Yes, the EU is failing. (b) Britain and most British-law based countries (the U.S., Canada, Australia, etc.) have some path to citizenship for migrant workers. The U.S. even gives automatic citizenship to any children born on U.S. soil (the only country in the world to do so). This is a big attractor.
In the light of crash rate theory, the high value of life in the sought-after country justifies the risk, and the high individual crash rate. But in a recent study of U.S. vs. German motorway death rates, I discovered that mixing these wealth levels affects the whole society. Such disparities may increase the crash rate of society. After all, the end of the Bronze Age was caused, at least in part, by Sea Peoples fleeing from Greece to other parts of the Mediterranean (speaking of deja vu!).
Science fiction came up with the ideas of the Prime Directive (Star Trek) and Non-Interference (SG-1) which hold that advanced civilizations should not give technology to developing civilizations, and in most cases should not even let their existence be known. Can you imagine if a nearby planet has immortality and star travel and enormous prosperity, the pressure to migrate there by any means at all? Heck, people want to go to Mars and there isn’t even anything there.
Crash rate theory implies that there may not only be risk to the more primitive civilization, but also risk to the advanced civilization. Crime rates, for example, are higher in mixed-wealth neighborhoods than either poor or rich neighborhoods. I suspect we may find there is a natural law that civilizations which do not adhere to the Prime Directive do not become space-faring civilizations – because they destroy themselves or regress backward from internal crashes.
Therefore efforts to contact ET are futile. The extraterrestrials will not respond, unless they are as messed up as we are. If you think a jet loaded with fuel causes a lot of damage, or a mere asteroid going 17,000 miles an hour, imagine the damage caused by an errant starship traveling a mere 10% of the speed of light (17,000 miles a second). Since energy is the square of velocity, it has 13 billion times the energy of the asteroid pound for pound. (3600 seconds in an hour, 3600 squared = 12.9 billion)
So it is not necessary to develop planet-destroying battle stations to conduct interstellar war. All you need to nix a planet is an ordinary unarmed star cruiser which can be misdirected.
In other words, anyone who seriously wants to be part of a star traveling civilization, should first leave Earth, never to come back. Assuming that it is unpalatable to exterminate the nearly-starfaring species on Earth. Although, given the fate of the Neanderthals, that may be what we have been doing.