In the 1950s or 1960s (I forgot), a lowly professor of electric engineering of West Germany went to East Germany and negotiated for a standardization of television broadcast encoding. A simple, non-political issue of defining technological standards. But with far-reaching geopolitical consequences.
That's why East Germany was able to receive and view western TV. And that's how the citizens of East Germany were able to see what life outside of their "socialist worker's paradise" was actually like. This ultimately led to the mass-protests in the late 1980s, which ultimately led to the collapse of the GDR in 1989.
Same thing with Ukraine. They are able to compare life in Europe and life in Russia.
Yanukovych wanted to play both sides and make deals with both sides, while secretly favoring Russia. Except that the EU said "us or them". Forced to make a hard choice between Europe and Russia, Ukraine broke apart along cultural fault-lines, with one half picking Europe and one half picking Russia.
And the same thing will happen with Cuba and North Korea.
The tourists will give Cuba a taste of freedom and the communist regime cannot hold them back forever.
The North Koreans know that they are being lied to and being oppressed, they just don't know what the rest of the world is like.
Information and an open clashes of ideas. Words! That's how Putin's Russia will be defeated. That's why North Korea is keeping its citizens uninformed and that's why russian trolls are busy planting fake stories all over the internet.