This one is kind of freaky. I made a sim family which saved to the sim bin. It consisted of a grandma, her son (adult), her grandson (young adult), her grandson's girlfriend, and their child who is a toddler. I had played them in Roaring Heights and then time passed so I started a new family. I made a Friends style household in a different city which consisted of the grandson and a bunch of other new people.
Here is where it gets weird. I sent the grandson to the tattoo shop from ambitions and the tattoo artist that spawned is the grandmother from the other world! She still spawns there. He got the tattoo. I was kind of weirded out by this grandma thing. Maybe she spawned because she is in the bin? She even kept her name.