What exactly happens if I use one cartridge and two 3DSes? Do I still get streetpass exclusive things? I've tried this in Yo-kai watch which has an infamously rare yo-kai you can only get through streetpassing and it's shown me some strange results. Since I used the same cartridge, the same save files are there and I can subsequently streetpass my self with my own save file. Does this actually do anything, or I am I just wasting my time?