(adsbygoogle = window.adsbygoogle || []).push({}); If I want to host a game, will people only from that region join me?

No. :-)

Not really. It's mainly based around your geographical location. If you are in a specific part of the world, people closest to your location will join your lobby. I know because I live in Western US using BLES01717 and people in LA were in my lobby.

That's really weird because when I host a game, I live in CA and I'm using BLES01717, and 80% of the time it's mexicans or french players, and 20% of the time north americans.

Could it be because of my shitty internet? Players not joining because the host has really shitty internet. (I'm running force host)

I'm not entirely sure how the force host thing works, and I choose not to use it because it always gives me weird problems. Maybe try disabling it?

It is definitely to do with geographical location, I live in the UK and my games are full of English, French or Spanish people if I join a friend that lives in the U.S then the lobby will be filled with people from that region, I believe Treyarch even spoke about this as a feature to help connection in games etc