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.

When I left my shipyard during construction, the blocks were actually lost. This happened twice. I have described the details in bug report T648.

I have always used either beams or cannons to attack stations. They constantly call for reinforcements but I have yet to ever see any come. Shooting stations does seem to increase my chance of seeing pirate spawns in other sectors I visit shortly afterward, from zero to some percentage.