I did this in the D&D game I'm running mostly for kids, and at a pretty high level of world-building, too:
- Thanks to my son's background for his character, the world was subject to a devastating plague in the recent past.
- Another player portrayed her character as an escapee from a tiefling-dominated empire, where she was low-caste. So there's a tiefling-dominated empire in the game world, and the implications of its existence and activities have echoed across the setting.
- Another player decided his home island had been riven by civil war.
All of those details made it into the game world.
I guess I'll be earning Alexander's opprobrium, then.