something that I've noticed with many planets in SF : the author often treats a planet like it's a small town, where two people keep bumping into each other at random intervals
take for instance earth : even if you were the only people on earth and you start to travel around in order to find the other person, what is the chance that you'd be successful ? pretty slim, I'd say - it's already hard enough to find your wife in the supermarket after you've lost sight of her ?
so why does it happen so often in SF stories ? sure, the story line may require it, but it remains pretty implausible
On occasions I've had to call the wife on her phone in that situation - they just disappear.
But the implausibility of SF is required by the plot. Take Jules Verne's The Time Machine. He travels forwards in time and, surprise surprise, he is exactly where the future civilisation is. This is less plausible than the actual time travel, but otherwise the film would be his wandering all over the globe, and that would be even more boring. It's another exercise in suspension of disbelief.