I traded with my black1 game and my avatar came visiting and set up a shop so BW1 people who run into while trading also come along. Also I noticed any person you interact in a GTS negotiation will end up showing up too whether if you trade anything or not. So if you just want to grab a bunch of people you could just pop into the GTS negotiations a few times or I would imagine playing against random people and throwing the matches to end the fast could be a quick alternative for people. I suppose you could do the whole magnemite thing too.
Ohhh, so that's why I ran into myself. A thousands thanks for unintentionally answering my question.