this is interesting... my thoughts...
After the throttle body is closed, the system (between throttle body and outlet of compressor) is a pressured closed system correct? in a pressured closed system of air, it shouldnt matter where the "hole" is located cos the idea is to relieve pressure. Just like how the BOV is on the pipe at a 90 deg angle. As long as u have a hole somewhere in the system, pressure will be lowered.
However, in addition, I think GTSBoy is also talking abt airflow and this disruption in momentum if the BOV is located far away from the point of direction reversal.