I traded with someone and he/she didn't have any country listed.
There is a "None" location in the script. He must have changed it somehow... I wonder how.
That may explain while a recent trade didn't mark on my map (unless the dude was from a area I had marked already)
Nah, it's because the people that aren't marked are just too lazy or didn't know you could talk to the globe, so they haven't set their location yet.
My current team:
Level 36 Level 36 Level 37 Level 36 Level 36 Level 37
I got a ニャルマー on GTS today from someone in Japan. :P