AFAIK tradestations have never called in response fleets (nor had a message pop up indicating that they should, I had assumed this was intended along with the tradestations being invulnerable)
As for weapons that don't trigger the fleets on pirate stations I have tested:
-Beam: does not spawn
-Cannon: does not spawn
-Missile: does not spawn

Hi,

I've noticed this as well on the Hyper-core server and have realized that warping/flying one sector above on the Y axis will locate the pirate fleet. I've tested this multiple times, where I approach the pirate fleet and they are not in motion. I think the issue is that the fleets aren't traveling to their targets.

I have read somewhere that players are supposed to be completely safe from NPCs while within the radius of a shop, however this is not what I see. The shop makes no move to retaliate when attacked. NPCs do not begin firing at a player that is already within the buy radius of the shop but if the player is being shot at and moves within the radius, the NPCs will continue shooting at least for a while. I didn't last very long testing this, but I was within the shop radius for at least nearly ten seconds while still having shots whizz past me, I don't think they were simply in flight before I entered the radius, especially since I was actively moving to evade fire and still got hit eventually. This happened twice, both on multiplayer from what I believe are custom NPCs unique to the server.