Hub-and-spoke routing + "it's not a small world, it's a small social class/industry/demographic/what-have-you" + the tendency for industries to cluster geographically.
And what are the odds people meet in the first place? Those exact same factors are what make folks run into each other again later. It would actually be weird if you never ran into people you know.
>…Bangalore. Our trips had nothing to do with each other, other than we both work in tech and were visiting tech companies.
Bangalore is a tech city, and you both worked in tech. That's how you ran into each other.
And what are the odds people meet in the first place? Those exact same factors are what make folks run into each other again later. It would actually be weird if you never ran into people you know.
>…Bangalore. Our trips had nothing to do with each other, other than we both work in tech and were visiting tech companies.
Bangalore is a tech city, and you both worked in tech. That's how you ran into each other.