I think this illustrates how hard it is to write SF plots involving 'mundane' interstellar travel (no warp drives or wormholes) that make approximate sense in terms of the laws of physics but which also reflect the enormous energy required and the sheer complexity of the task. Going to a different star is nothing like going to the moon but with a much larger Apollo. Simple plot devices (there's something in the way that we didn't detect before launch and didn't otherwise consider) really don't stand up very well.