How are seats assigned to candidates? Is it pre-planned or random?
In everyone I’ve heard of, it’s random - in other words, first come, first served.
I also never heard about this.
Your seat is on your ticket number, your seat is not random but by candidate number. If you pass L1 you will likely sit next the same person again at L2 and L3.
provided THEY also pass… 
So I can find out next June if the incredibly nervous asian girl next to me also passed? Assuming she takes it in NY again.
Yep. I sat next the same guy over each of the 4x i did the exam (we both failed, retook and passed L3). It’s really strange seeing and chatting to that 1 person for 10mins 1 time per year over the 4yrs… We’re all in the same boat…absorbed by CFA.
What if I change exam place, country? This year I will take exam in Germany, next maybe in Croatia.