1. it would make every system into a copy of ny (lulz!)
2. it would ruin the surprise for many targets (*evil grin*)
srsly, it would be abused; the command to eavesdrop via hyperspace would be used by traders to avoid pirates, pirates to avoid police, and smugglers to avoid everybody. End result? pirates get bored and desperate, and start asking for money AND your life (cos they not got one due to sitting around waiting for a hapless freighter), police get bored and start attacking people on the most trivial of infractions, and smugglers get richer and richer. /powersmuggle
even the commodity could be abused: get a convoy together, drop these beacons in space every time you pass back and forth, each convoy captain keeping an eye on their system... they completely avoid pirates. /powertrade
lastly, how would you tell the difference between your system and the target system?
would you have to re-enter the code each time you changed system?
and would a /eavesdrop <player> command be more useful?