I suggest for no NPC ships to spawn in quadrants with docks.
It's not my intention to call anybody out here, but I've noticed a trend with players (on all sides, really) parking their ships in quadrants with docks to camp for NPC ships while staying ready to dock the moment another PC ship shows up.
At that point it's no longer sailing but it pretty much becomes dungeon instancing with the intent of avoiding other player characters during a PvE grind.
This doesn't concern only town ports with low level PvE content either - there are quadrants with docks all around the sailing map even in regions with endgame PvE ships.