Totally unmarked ?Like no signage at all? no light, no stop sign, no yield sign? The other driver is treating it like a four way stop,which is safe, and probably expecting other drivers to do the same,and if they do the first guy should then go, but since no signage at all I guess it’s a free for all, and the first driver was still playing safe to see if the other driver would stop or just plow right through.