Unfortunately, I disabled the event 'wander joins' on this scenario, so this won't happen either 
I think the only remaining possibility is someone contacting me to join my colony because they are chased by a raid.
While it's not totally hopeless, this is very unlikely to get any better.

I think the only remaining possibility is someone contacting me to join my colony because they are chased by a raid.
While it's not totally hopeless, this is very unlikely to get any better.