How civilisations can spread across a galaxy

kanweg writes: If you look at the milky way at night, it appears not much is changing. But over time, stars get closer and further to each other. Coryn Bailer-Jones, an astrophysicist at Germany’s Max Planck Institute for Astronomy in Heidelberg, found that of 14 stars coming within 3 light years of Earth, the closest encounter is likely to be HIP 85605, which now lies some 16 light years away in the constellation of Hercules. It will get a close as the Oort cloud.
Human or alien civilisations could practice star hopping. Why travel 16 light years through space when you can just wait until a star with a suitable planet gets close and cover only the last stretch with an artificial spaceship? Take your time for a thoughtful response; it will take another 250,000 to 470,000 year before the close encounter.