I'm super excited for this. I think its' just a good piece of advice to not over-link things. it can make a world feel very small. one or two "oh, and this is someone you know!" here and there, maybe one or two per player kind of keeps it integrated without being overly coincidental.
The best back story i ever made was a dog who was basically lassy. Smart ones right from wrong basically a ' good' dog. Unfortunately no one would let a stray dog join they're group. So he befriended a small child and lured the child off to play . . . Now having a human compain people would let the dog join the team. Needless to say. If the kid wanted to stop or not do as the dog wanted. he ended up down a well XD and a new ' friend 'was found :D. It was the most hated character I ever made. But I love the fluff